Acides aminés (AA)

Applications 2-methyl-1-[4-(trifluoromethyl)phenyl]propan-1-one (cas# 64436-58-4) is a useful research chemical.

Applications 3-Formyl-5-methylbenzoic Acid

Applications 3-Methylbutane-1,2,3-tricarboxylic Acid is an atmospheric oxidation product of α-pinene that is a tracer compound for atmospheric terpene secondary organic aerosol (SOA) particles.
Not a dangerous good if item is equal to or less than 1g/ml and there is less than 100g/ml in the package
References Dette, H.P., et. al.: J. Phys. Chem. A., 118, 7024 (2014)

Stability Moisture Sensitive
Applications Used in conjunction with Isothiocyanate to conduct partial Edman Degradation on biologically active peptides.
Not a dangerous good if item is equal to or less than 1g/ml and there is less than 100g/ml in the package
References Heidenreich, O., et al.: J. Biol. Chem., 269, 2131 (1994), Kothe, U., et al.: Anal. Biochem., 356, 148 (2006), Thakkar, A., et al.: Anal. Chem., 78, 5935 (2006),

Applications 4-Methyl-5-thiazoleethanol is used in the synthesis of novel HldE kinase inhibitors used against gram negative bacteria. Also used in the synthesis of potential antimalarial agents from bis-thiazolium analogues.
Not a dangerous good if item is equal to or less than 1g/ml and there is less than 100g/ml in the package
References Desroy, N. et al.: J. Med. CHem., 56, 1418 (2013); Caldarelli, S. et al.: J. Med. CHem., 496, (2013);

Applications 2-Methylpentane is used as a raw material/intermediate in organic synthesis, rubber solvent, and vegetable oil extraction solvent.
References Choi, D., et al.: Adv. Funct. Mater. 25, 920 (2015)

Applications An intermediate in the synthesis of Erlotinib (E625000).

Applications L-Lysine L-Malate is used in the preparation of amino acid ionic liquids for use in food and medical field.

Applications A Boc-protected bifunctional linking reagent.
References Jimenez-Castells, C., et al.: Bioorg. Med. Chem. Lett., 17, 5155 (2007), Carmona, S., et al.: Mol. Pharm., 6, 706 (2009), Nagahori, N., et al.: Biochem., 48, 583 (2009),

Applications 4-Methoxy-3-nitrobenzonitrile

Applications 4-Methylimidazole is a monomethylated imidazole that can be used as a building block in the preparation of a wide range of biologically active compounds. 4-Methylimidazole is a product which results from the interaction of reducing sugars with ammonia. 4-Methylimidazole showed convulsant activity in animals and is listed as a possible carcinogen.
Not a dangerous good if item is equal to or less than 1g/ml and there is less than 100g/ml in the package
References Nishie, K. et al.: Toxicol. Appl. Pharmacol., 14, 301 (1969): Cunha, S.C. et al.: J. Food Comp. Anal., 24, 609 (2011); Chan, P.C. et al.: Arch. Toxicol., 82, 55 (2008);

Applications (S)-2-(4-CHLOROPHENYL)-3-METHYLBUTANOIC Acid (cas# 55332-38-2) is a useful research chemical.

Applications 2-Oxo-3-methylbutanoic acid (cas# 759-05-7) is a useful research chemical.
Not a dangerous good if item is equal to or less than 1g/ml and there is less than 100g/ml in the package

Applications (2-hydroxy-4-methoxyphenyl)(4-methylphenyl)methanone (cas# 1641-17-4) is a useful research chemical.

Applications 4-Chloro-4-methyl-1-pentene affects the surface modification of Kevlar stitch threads on mechanical interfacial properties of carbon fiber and bismaleimide stitched composites.
Not a dangerous good if item is equal to or less than 1g/ml and there is less than 100g/ml in the package
References Ai, T., et al.: Fuhe Cailiao Xuebao, 24, 34-39 (2007)

Applications 1-Ethyl-1-methylcyclopentane, is one of the chemical components of Gas-Phase organic carbon emissions from motor vehicles. It is also a volatile component of frying oils.
References Gentner, D. R., et al.: Environ. Sci. Tech., 47, 11937 (2013); Prevot, A. Frying Food, 155 (1988);

Applications 2-Methoxy-1-[4-(oxiranylmethoxy)phenyl]ethanone (cas# 110458-44-1) is a compound useful in organic synthesis.

Applications 1-Bromo-3-methylbutane, is used as an extraction solvent to determine various polycyclic aromatic hydrocarbons in water samples though dispersive liquid-liquid microextraction along with GC-MS (gas chromatography- mass spectrometry).
Not a dangerous good if item is equal to or less than 1g/ml and there is less than 100g/ml in the package
References Rezaee, M., et al.: J. Chromat. A., 1116, 1 (2006)

Impurity Cefoperazone EP Impurity C
Applications N-Methyl-5-tetrazolethiol (Cefoperazone EP Impurity C) is an impurity of Cefoperazone.
References Kitson, T., et al.: Biochem. J., 175, 83 (1978), Elenbaas, R., et al.: Clin. Pharmacol. Ther., 32, 347(1982),

Applications Tris(2-(2-methoxyethoxy)ethyl)amine (cas# 70384-51-9) is a useful research chemical.

Applications Labelled 4-Methoxyestrone (M226135). An endogenous estrogen metabolite, risk-factor for development of breast cancer.
References Beral, V., et al.: Lancet, 362, 419 (2003), Nelson, R., et al.: Clin. Chem., 50, 373 (2004), Malekinejad, H., et al.: J. Agric. Food Chem., 54, 9785 (2006),

Applications N-(2-Methyl-1-phenylpropan-2-yl)acetamide is a byproduct from the preparation of benzolactams by palladium-catalyzed carbonylation of arylethylamines and α-amino benzenepropanoates.
References Lopez, B., et al.: Chem. Commun., 47, 1054 (2011); Albert, J., et al.: Organometallics, 32, 649 (2013);

Applications 4-Bromo-6-methyl-3H-1,3-benzodiazole

Applications 1-Methyl-2-pyrrolidinone-d9 is labeled 1-Methyl-2-pyrrolidinone (M326120), which is a versatile industrial solvent. NMP is currently approved for use only in veterinary pharmaceuticals. The determination of the disposition and metabolism of NMP in the rat will contribute toward understanding the toxicology of this exogenous chemical which man may likely be exposed to in increasing amounts.
References Southwell, D., et al.: J. Pharm. Pharmacol., 33, 3 (1981), Barry, W., et al.: J. Invest. Dermatol., 82, 49 (1984),

Applications 4-Methylfluorene is a polycyclic aromatic hydrocarbon that has been found to be emitted by wastewater treatment facilities.
References Zhang, W., et. al.: Sci. Total Environ., 432m 396 (2012)

Applications 2,4-Dinitrophenylhydrazone (DNPH) derivative.
References Lindsay, R.C., et al.: J. Food Sci., 29, 266 (1964),

Stability Temperature Sensitive
Applications Precursor of Diazomethane. It has a cytotoxicity effect.This product contains an undetermined amount of water.
Not a dangerous good if item is equal to or less than 1g/ml and there is less than 100g/ml in the package
References Huggins, C., et al.: J. Exp. Med., 131, 321 (1970), Gullino, P.M., et al.: J. Natl. Cancer Inst., 54, 401 (1975),

Applications Methyl 4-Methyl-3-hydroxybenzoate is used in the preparation of potent antimalarial agents. Also used in the preparation of aromatic inhibtors of anthranilate synthase.
References Fattorusso, C. et al.: J. Med. Chem., 51, 1333 (2008); Payne, R. et al.: Org. biomol. Chem., 3, 3629 (2005);

Applications N-Acetyl-S-(3-hydroxypropyl)-L-cysteine Dicyclohexylamine Salt (unlabelled) (CAS# 14369-42-7) is a useful research compound.

Applications N-Fmoc-L-tyrosine Benzyl Ester is used to synthesize truncated analogues of preptin-(1-16) as possible osteoblast proliferation stimulant. It is also an intermediate used to prepare phosphotyrosinyl phosphoramidite derivatives useful in the incorporation of multiple reporter groups on synthetic oligonucleotides.
References Kowalczyk, R., et al.: Bioorg. Med. Chem., 22, 3565 (2014); Misiura, K., et al.: Nucl. Acids Res., 18, 4345 (1990)

Applications 3-Methyl-d3-4-nitrophenol-2,5,6-d3 (CAS# 1219803-89-0) is a useful isotopically labeled research compound.

Applications Ac-lys(ac)-oh was used in the reaction of HOCl with amino acids and peptides with ESR evidence for rapid rearrangement and fragmentation reactions of nitrogen-centered radicals.
References Hawkins, C., et al.: J. Chem. Soc. Perkin Trans. 2, 9, 1937 (1998);

Stability Hygroscopic
Applications Hexanoyl-L-carnitine-(N-methyl-d3) Chloride, is the labeled analogue of Hexanoyl-L-carnitine Hydrochloride (H294440), which is used as reactant in the synthesis of carnitine benzyl esters as prodrugs.
References Gong, X., et. al.: J. Chem. Res., 6, 327 (2008)

Applications N,N'-Di-4-pyridinyl-methanediamine is used to prepare bis(heteroaryl)-imidazolidinediones with oxalyl chloride.
References Ghandi, M., et al.: Synth. Comm., 37, 637 (2007)

Applications N-Boc-4-hydroxypiperidine is a 4-hydroxypyridine with a boc protecting group used in the preparation of neurologically active agents and other pharmaceutical compounds.
References Kwon, Y.E. et al.: Bioorg. Med. Chem., 15, 6596 (2007); Knutsen, L.J.S. et al.: J. Med. Chem., 42, 3463 (1999);

Applications N-(2-Hydroxyethyl)glycine (~90%) (cas# 5835-28-9) is a compound useful in organic synthesis.

Applications 2-Methoxytetrahydrofuran is a reactant in the preparation of ruthenium(III) chloro benzimidazolylmethylamine derivative complexes as oxidation catalysts.
References Murali, M., et. al.: Eur. J. Inorg. Chem., 22, 3238 (2009)

Applications Used in the synthesis of Capsaicin analogues, useful for their anti-tumor activity.
References Fusco, B., et al.: Drugs, 53, 909 (1997), Buisman, G., et al.: Biotechnol. Lett., 20, 131 (1998), Kobata, K., et al.: Bios. Biotechnol. Biochem., 66, 319 (2002), Aluru, M., et al.: J. Exp. Bot., 54, 1655 (2003),; Wang, W. et al.: Gaodeng Xuexiao Huaxue Xuebao 31, 2400(2010)

Impurity Carvedilol EP Impurity E; Carvedilol Impurity E; Carvedilol USP E
Applications 2-(2-Methoxyphenoxy)ethylamine Hydrochloride (Carvedilol EP Impurity E; Carvedilol Impurity E; Carvedilol USP E) is an impurity of Carvedilol synthesis.
References Smith, L., et al.: J. Med. Chem., 20, 1653 (1977),

Applications Sodium 2,2'-Methylene-bis(4,6-di-tert-butylphenyl)phosphate is an organophosphate nucleating agent.
References Li, J., et al.: Suliao, 43, 47-50 (2014);

Applications 1-Methyl-4-(phenylmethyl)piperazine hydrochloride is a useful synthetic intermediate.

Applications 4-Benzyloxy-3-methoxybenzoic Acid is used in the synthesis of Hsp90 inhibitors as EGCG analogues. Also used in the preparation of vanillates exhibiting cytostatic properties towards cancel cells resistant to pro-apoptotic stimuli.
References Khandelwal, A. et al.: J. Org. Chem., 78, 7859 (2013); Lamoral-Theys, D. et al.: Bioorg. Med. Chem., 18, 3823 (2010);

Applications Labelled Isoferulic Acid 3-O-β-D-Glucuronide, the glucuronide conjugate of Isoferulic Acid (H946180). Isoferulic Acid 3-O-β-D-Glucuronide is one of the circulating metabolites in human plasma after coffee consumption.
References Fumeaux, R. et al.: Org. Biomol. Chem., 8, 5199 (2010); Redeuil, K. et al.: J. Chrom. A, 1218, 4678 (2011);

Applications A labelled, essential amino acid.
References Liu, F., et al.: Bioorg. Med. Chem., 18, 4167 (2010), Kumar, R., et al.: Eur. J. Med. Chem., 45, 2265 (2010), Cai, W., et al.: Bioorg. Med. Chem., 18, 1899 (2010),

Applications N-Methyltaurine can be used as a counter ion in the formation of soaps.
References Miyahara, Reiji, et al.: J. of Oleo Sci., 50(10), 823-830 (2001)

Applications DL-Homocysteine-d4 is used in the detection of the biosynthetic pathway for the formation of volatile aroma compound 2-methyltetrahydrothiophen-3-one by the bacterium Chitinophaga.
References Nawrath, T., et al.: ChemBioChem., 11, 1914-1919 (2010)

Applications 3-Methoxypropanoic acid

Applications Potent crosslinking inhibitors.
References Sloan, J., et al.: J. Biol. Chem., 274, 23740 (1999).

Applications 2-Cyano-N-methylacetamide is used in the synthesis of pyridone compounds and benzimidazoles, for various pharmaceutical application.
References Mijin, D. et al.: Synth. Comm., 36, 193 (2006); Grimmett, M. et al.: Sci. Synth., 12, 529 (2002); Aggarwal, V. et al.: Synth. 3, 214 (1982);

Applications Labelled analogue of L-Vailne. L-Valine is an essential amino acid and one of 20 proteinogenic amino acids. L-Valine cannot be manufactured by the body and must be acquired through diet or supplementation. L-valine is found in grains, dairy products, mushrooms, meats, peanuts and soy proteins. L-Valine has been used in studies to attenuate arrhythmias and induce hypotensive effects.
References Choi, C.W. et al.: Anim. Feed Sci. Technol., 102, 15 (2002); Kolarski, D. et al.: Krmiva, 30, 155 (1988); Oba, M. et al.: J. Dairy Sci., 93, 2044 (2010); Mitrega, K. et al.: Pharmacol. Res., 64, 218 (2011);

Impurity Iohexol EP Impurity K
Applications 5-Amino-2,4,6-triiodoisophthalic Acid (Iohexol EP Impurity K) is an intermediate for nonionic iodinated X-ray contrast agents.

Applications Suberylglycine is one of the acylglycines, an important class of metabolites that have been used in the diagnosis of several inborn errors of metabolism (IEM).
References Costa, C., et al.: J. Pharmaceut. Biomed. Anal., 21, 1215 (2000), Garcia-Villoria, J., et al.: Clin. Biochem., 42, 2 (2009), Scalbert, A., et al.: Metabolomics, 5, 435 (2009),

Applications A labelled metabolite of Catecholamines.
References Kopin, I.J., et al.: J. Biol. Chem., 236, 2109 (1961), Short, F.W., et al.: J. Med. Pharm. Chem., 5, 642 (1962)

Applications Isotope labelled L-Serine, used in the synthesis of purines and pyrimidines as antibacterial/antifungal agents, as well as acting as a proteinogenic compound.
References Olivella, M. et al.: Bioorg. Med. Chem., 20, 6109 (2012);

Applications Valeric Acid Sodium Salt (cas# 6106-41-8) is a compound useful in organic synthesis.

Applications Labelled analogue of L-Phenylalanine, an essential amino acid.
References Hollunger, G. et al.: Acta Pharmacol. Toxicol., 34, 391 (1974); Bagchi, S.P. et al.: Biochem. Pharmacol., 26, 900 (1977);

Applications L-Glutamine (Alpha-15n, 98%) (cas# 80143-57-3) is a useful research chemical.

Stability Hygroscopic
Applications A labelled metabolite of Acrylonitrile (ACN).
References Guengerich, F., et al.: Cancer Res., 41, 4925 (1981), Leonard, A., et al.: Mutation Res., 436, 263 (1999), Stadler, R., et al.: J. Agric. Food Chem., 52, 5550 (2004), Dybing, E., et al.: Food Chem. Toxicol., 43, 365 (2005), Rice, J., et al.: Mutation Res., 580, 3 (2005),

Stability Very Hygroscopic
Applications 1-O-Dimethoxytrityl-2-(N-Fmoc)-4-Aminobutyl)-1,3-propanediol is a useful reagent for the synthesis of acridine and​/or lipid containing oligodeoxyribonucleotides.
References Marasco, C. J., et al.: Tetra. Lett., 35, 3029 (1994)

Applications A labelled metabolite of Toluene.
References Gargas, M., et al.: Toxicol. Appl. Pharmacol., 98, 87 (1989), Commandeur, J., et al.: Pharmacol. Rev., 47(2), 271 (1995), Campo, P., et al.: Neurotoxicol. Teratol., 21, 427 (1999), Lohse, C., et al.: J. Agr. Food Chem., 48, 5913 (2000),

Applications Thiodiglycolic Acid-d4 acts as a reagent for the synthesis of metabolites of S-carboxymethyl-L-cysteine and S-methyl-L-Cysteine and of some isotoically labelled (2H, 13C) analogs.
References Meese, C. O., et al.: Archiv der Pharmazie, 323, 957 (1990)

Applications N-Epsilon-acetyl-l-lysine is used in the metabolomics study on the combined effect of cocaine and ethanol via liquid chromatography-mass spectrometry metabolomics approach.
References Sanchez-Lopez, E., et al.: J. Pharm. Biomed. Anal., 140, 313 (2017)

Applications Useful in the study of tyrosine-phosphorylation, which has been linked with the malignant transformation of cells by some RNA tumour viruses.
References Sefton, B.M., et al.: Cell, 20, 807 (1980), Erikson, R., et al.: Perspect. Virol., 11, 93 (1981), Lee, E-S, et al.: J. Org. Chem., 59, 2086 (1994)

Applications L-Valine is an essential amino acid and one of 20 proteinogenic amino acids. L-Valine cannot be manufactured by the body and must be acquired through diet or supplementation. L-valine is found in grains, dairy products, mushrooms, meats, peanuts and soy proteins. L-Valine has been used in studies to attenuate arrhythmias and induce hypotensive effects.
References Choi, C.W. et al.: Anim. Feed Sci. Technol., 102, 15 (2002); Kolarski, D. et al.: Krmiva, 30, 155 (1988); Oba, M. et al.: J. Dairy Sci., 93, 2044 (2010); Mitrega, K. et al.: Pharmacol. Res., 64, 218 (2011);

Stability Hygroscopic, Temperature Sensitive
Applications A carnitine ester of unsaturated fatty acid. Used in the studies of fibroblasts in long-chain 3-hydroxyacyl-CoA dehydrogenase deficiency and fatty acid oxidation disorders.
References Gross R.W., et al.: J. Biol. Chem., 258, 5221 (1983),

Applications Labelled analogue of L-Phenylalanine, an essential amino acid.
References Hollunger, G. et al.: Acta Pharmacol. Toxicol., 34, 391 (1974); Bagchi, S.P. et al.: Biochem. Pharmacol., 26, 900 (1977);

Applications (3R)-Tetrahydrofuran-3-yl 4-Methylbenzenesulfonate is derived from (R)-(-)-3-Hydroxytetrahydrofuran (H957760), which is a versatile chemical reactant used in the synthesis of pharmaceutical agents.
References Hrapchak, M., et al.: J. Labelled. Comp. Radiopharm., 57, 687 (2014);

Applications Butyrylglycine is one of the acylglycines, an important class of metabolites that have been used in the diagnosis of several inborn errors of metabolism (IEM).
References Costa, C., et al.: J. Pharmaceut. Biomed. Anal., 21, 1215 (2000), Garcia-Villoria, J., et al.: Clin. Biochem., 42, 2 (2009), Scalbert, A., et al.: Metabolomics, 5, 435 (2009),

Impurity Tinidazole EP Impurity A/ Metronidazole EP Impurity A
Applications 2-Methyl-5-nitroimidazole (Tinidazole EP Impurity A) is a Floconazole impurity.
References Sanderson, H., et al.: Toxicol. Lett., 187, 84 (2009), Kumar, L., et al.: Eur. J. Med. Chem., 45, 817 (2010),

Applications An endogenous antidiuretic hormone in most mammalian species. It is released into the blood from nerve terminals in the posterior pituitary and median eminence. It is a neurotransmitter in the central nervous system and also implicated in a variety of physiological processes such as regulating water balance by antidiuretic action. It is a peptidic V1a receptor agonist that produces vasoconstriction via V1aR-mediated vascular smooth muscle cell contraction and is being used to increase blood pressure in septic shock, a form of vasodilatory hypotension.
References Perucca, J. et al.: J. AM. Soc. Nephrol., 19, 1721 (2008); Toba, K. et al.: Prog. Brain Res., 119, 337 (1998); Berrada, K. et al.: J. Biol. Chem., 275, 27229 (2000);

Applications A serine derivative. Used in the synthesis of constrained amino acid buildings blocks and their incorporation into biologically active peptidomimetics.
References Rew, Y., et al.: J. Med. Chem., 45, 3746 (2002),

Applications N-(1H-pyrrol-2-ylcarbonyl)-Glycine has been used as a diagnostic marker of hyperprolinemia type II.
References Walker, V., et al.: Clinica Chimica Acta, 405, 153 (2009).

Applications N-Methyl-dl-valine, HCl

Stability Hygroscopic
Applications Lauryl Betaine is an amphoteric surfactant derived from N-dodecyl-N,N-dialkanol amine with protein denaturing potency. Lauryl Betaine is mainly used in shampoo, personal hygiene products and oil field chemicals.
Not a dangerous good if item is equal to or less than 1g/ml and there is less than 100g/ml in the package
References Kimura, Y. et al.: J. SCCJ, 29, 106 (1995); Qin, C. et al.: GUang. Huag., 34, 30 (2006); Peng, Z. et al.: Riy. HUax. Gong., 37, 135 (2007);

Applications N-[(Benzyloxy)carbonyl]glycylglycine is a reagent in the synthesis of Glycylglycyl-L-tyrosine (G718500), which is a fungal tyrosinases and their capability to oxidize peptide-bound tyrosine residues is important in a view of applicability of tyrosinases.
References Bowness, J., et al.: Biochem. J., 53, 620 (1953), Cuff, M., et al.: J. Mol. Biol., 278, 855 (1998), Kubo, I., et al.: Bioorg. Med. Chem., 12, 5349 (2004),

Applications Pipecolic acid is involved in synaptic transmission in the central nervous system. The l-form occurs in plants.
References Nomura Y., et al.: Neurochem. Res., 6, 391 (1981),

Applications N-ACETYLISOLEUCINE (cas# 3077-46-1) is a useful research chemical.

Applications Labelled DL-Pipecolinic Acid (P479762). Pipecolic acid is involved in synaptic transmission in the central nervous system.
References Nomura Y., et al.: Neurochem. Res., 6, 391 (1981),

Applications L-Aspartic Acid is a non-essential amino acid found in food sources. L-Aspartic Acid is one of the 20 proteinogenic amino acids; the building blocks of proteins. Its conjugate base L-aspartate is an excitatory neurotransmitter in the central nervous system.
References Ager, D.J. et al.: J. Mol. Catal. Enzym., 11, 199 (2001); Velisek, J. et al.: Cze. J. Food. Sci., 24, 1 (2006); Nagahama, M. et al.: Cell Tiss. Res., 318, 483 (2004);

Applications N-Acetyl-L-phenylalanine is an protected analogue of L-Phenylalanine (P319415), an essential amino acid produced for medical, feed, and nutritional applications such as in the preparation of Aspartame.
References Sriram, S., et al.: J. Med. Chem., 56, 2540 (2013); Parker, B.M., et al.: J. Biotech., 155, 396 (2011);

Applications Acetyl-d3 L-Carnitine Hydrochloride is labelled Acetyl L-Carnitine Hydrochloride (A171990) which is used for transmembrane action potential studies. Acetylcarnitine has antinociceptive activity that may be mediated by enhanced activity of muscarinic cholinergic receptors or mGlu2 glutamate receptors.
References Matsui, K., et al.: Japanese J. Pharmcol., 39, 263 (1985); Chlechio, S., et al.: J. Endocrinol. Invest., 27, 171 (2004): Walker, R., et al.: Comparative General Pharmacol., 4, 65 (1973)

Applications Increased levels lead to hyperhomocysteinemia; a cardiovascular risk factor in prediction of coronary heart disease as well as being associated with congenital birth defects, pregnancy complications and cancer.
References Geisel, J. et al.: Clin. Chem. Lab. Med., 41, 1513 (2003); Geisel, J. et al.: Clin. Chem. Lab. Med., 41, 1513 (2003);

Applications 2,6-Diaminopimelic Acid is useful in biological studies involving amino acids and amino sugars as molecular indicators of the origins of organic matter in buried tephra soils.
References Hobara, S., et al.: Geoderma, 373, 114449 (2020)

Applications Useful for the synthesis of Biocytin containing peptides to study the mechanism of reactions catalyzed by biotin - containing enzymes.
References Bodanszky, M., and Fagan, D.T.: J. Am. Chem. Soc., 99, 235 (1977)