Carbamic acid, -, 1,1 -dimethylethyl ester

C7H,5N04 86780-81-6) see Aranidipine (4-aminobutyl)[3-[[(l,l-dimethylethoxy)carbonyl]amino]-propyl]carbamic acid 1,1-dimethylethyl ester... 

C4H5NO 693-93-6) see Pyridoxine 4-methyioxazole-5-carboxamide (C,H,N202 4866-00-6) see Pyridoxine 2-methyl-4-(oxiranylmethoxy)-l//-indole (C 2HnN02 62119-47-5) see Bopindolol Mepindolol (2S-/rans)-(2-methyl-4-oxo-3-azetidinyl)carbamic acid 1,1-dimethylethyl ester (C HlhN 0, 80582-03-2) see Aztreonain... 

C,0H17O4P 70073-58-4) see lloprosl 4-methyl-l-(2-oxo-2-phenylethyl)pipcrazine (CnH 8N20 41298-85-5) see Hexocyclium metilsulfatc (ZS -frans)- 2-methyl-4-oxo-l-(phcnylmcthoxy)-3-azetidi-nyl]carbamic acid 1,1-dimethylethyl ester (C fiH22N204 75659-16-4) see Aztreonam... 

Patel RN, Chu L, MueUer RH. Diastereoselective microbial reduction of (S)-[3-chloro-2-0X0-l-(phenylmethyl)propyl]carbamic acid, 1,1-dimethylethyl ester. Tetrahedron Asymmetry 14(20), 3105, 2003. 

Atazanavir 21 (Figure 4.23) is an acyclic aza-peptidomimetic, a potent HIV protease inhibitor [44, 45] approved by the FDA for the treatment of acquired immunodeficiency syndrome (AIDS). An enzymatic process was developed to prepare (lS,2i )-[3-chloro-2-hydroxy-l-(phenylmethyl) propyljcarbamic acid, 1,1-dimethylethyl ester 81, a key chiral intermediate in the S5mthesis of atazanavir. The diastereoselective reduction of (lS)-[3-chloro-2-oxo-l-(phenylmethyl)propyl] carbamic acid, 1,1-dimethylethyl ester 82 was carried out using Rhodococcus erythropolis to afford 81 with a >90% yield and with a diastereomeric purity of >98% and an ee of 99.4% [111],... 

Atazanavir enzymatic synthesis of (1S,2/ )-[3-chloro-2-hydroxy-1(phenylmethyl) propyl]-carbamic acid,1,1-dimethylethyl ester. 

Ethoxypyrrolin-5-one l-Pyrrolin-5-one, 2-ethoxy- (8) 2H-Pyrrol-2-one, 5-ethoxy-3,4-dihydro- (9) (29473-56-1) tert-Butyl N-(l-ethoxycyclopropyl)carbamate Cyclopropanecar-bamic acid, 1-ethoxy-, tert-butyl ester (8) Carbamic acid, (1-ethoxycyclopropyl)-, 1,1-dimethylethyl ester (9) (28750-48-3 41879-49-6)... 

S)-3-(tert-Butyioxycarbonyiamino)-1 -diazo-4-phenyibutan-2-one Carbamic acid, [3-diazo-2-oxo-1-(phenyimethyi)propyi]-, 1,1-dimethylethyl ester, (S)- (9) (60398-41-6) Boc-Phenylaianine L-Phenyiaianine, N-[(1,1-dimethylethoxy)carbonyl]- (9) (13734-34-4) Trie yiamine (8) Ethanamine, N,N-diethyl- (9) (121-44-8)... 

METHYLBUTYL)-, 1,1-DIMETHYLETHYL ESTER, (S)- (5821-45-2), 67, 69 N-tert-Butoxycarbonyl-L-leucine N-methyl-O-methylcarboxamide Carbamic acid, [1-((methoxymethylamino)carbonyl]-3-methylbutyl]-, 1,1 -dimethylethyl ester. (S)- (87694-50-6), 67, 69... 

N-tert-BUTOXYCARBONYL-L-LEUCINAL (Carbamic acid, (l-fonnyl-3-inethylbutyl)-, 1,1-dimethylethyl ester, (S)-)... 

N,N -Di-Boc-N"-triflylguanidine N,N -Bis(tert-butoxycarbonyl)-N"-trifluoromethane-sulfonylguanidine Carbamic acid, [[(trifluoromethyl)sulfonyl]carbonimidoyl]bis-, bis(1,1-dimethylethyl) ester (14) (207857-15-6)... 

Furan-2-ylcarbamic acid tert-butyl ester Carbamic acid, 2-furanyl-, 1,1-dimethylethyl ester (9) (56267-47-1)... 

The synthesis of DPP-IV inhibitor Saxagliptin 5 also required (55)-5-amino-carbonyl-4,5-dihydro-lH-pyrrole-l-carboxylic acid, l-(l,l-dimethylethyl)ester 10 (Figure 16.3C). Direct chemical ammonolyses were hindered by the requirement for aggressive reaction conditions, which resulted in unacceptable levels of amide race-mization and side-product formation, while milder two-step hydrolysis-condensation protocols using coupling agents such as 4-(4,6-dimethoxy-l,3,5-triazin-2-yl)-4-methylmorpholinium chloride (DMT-MM) [41] were compromised by reduced overall yields. To address this issue, a biocatalytic procedure was developed based on the Candida antartica lipase B (CALB)-mediated ammonolysis of (55)-4,5-dihydro-lH-pyrrole-l,5-dicarboxylic acid, l-(l,l-dimethylethyl)-5-ethyl ester 9 with ammonium carbamate to furnish 10 without racemization and with low levels of side-product formation. 

An enzymatic process was developed using the CAL-B-mediated ammonolysis of (5S)-4,5-dihydro-lH-p3rrrole-l,5-dicarboxylic acid, l-(l,l-dimethylethyl)-5-ethyl ester 77 with ammonium carbamate to furnish 76 without racemization and with very low levels of side-product formation [104]. 

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