JV-acetylation

Pterin, 6,7,7-trimethyl-7,8-dihydro-bacteriostatic activity, 3, 325 Pterin, 5,6,7-trimethyl-5,6,7,8-tetrahydro-dihydrochloride monohydrate X-ray analysis, 3, 281 Pterin-6-carbaldehyde, JV -acetyl-synthesis, 3, 312... 

Treatment of the carbanion derived from 94 with nitriles was shown to give enaminesulfoxides 136, which can be converted to a-ketoesters or a-ketoacylamides185, besides the ester of JV-acetylamino acid 137. Using this reaction, the methyl ester of dl-JV-acetyl-5-hydroxytryprophane 138 was synthesized186. 

Fig. 5.—Parallel packing arrangement of the 2-fold helices of chitin I (3). (a) Stereo view of two unit cells approximately normal to the hc-plane. The two comer chains (open bonds), separated by b, in the back are hydrogen bonded to the comer chains (tilled bonds) in the front, (b) Projection of the unit cell along the c-axis with a down and b across the page. The diagonal orientation of the sugar rings facilitates interchain hydrogen bonds involving the JV-acetyl moieties along the a-axis.

A selective 6-acetylation of the following diglucoside in 71% yield by JV-acetyl-imidazole has been reported [200]... 

In penicillinbehandelten Staphylokokken wurde, an Uridindiphos-phat glykosidisch gebunden, eine MoRGAN-ELSON-positive Saure ge-funden, bei der es sich moglicherweise um eine JV-Acetyl-hexosamin-uronsaure handelt (206). 

Synthesis of GAGs requires the sequential attachment of an jV-acetyl amino sugar or uronic acid to the protein core molecule (Figure 9.2), each step being catalysed by a... 

Vasella has applied the concept of anomeric anion stabilization by a nitro group to the /3-D-JV-acetyl-D-glucosamine derivative 177, available in four steps from N-acetyl-n-glucosamine [52] (Scheme 39). Reaction of the tetraethylammonium nitronate derived from 177 with aldehyde 178 provides anti-179 which then undergoes stereoselectively reduction (see Sect. 2.2.1) to provide -C-glycoside 180, intermediate in a synthesis of N-acetyl-neuraminic acid. 

Lindlar s catalyst (5% Pd on CaC03, poisoned with Pb, 250 mg) and the mixture was hydrogenated at 0.2 MPa for 35 min at rt. TLC showed the conversion of azide [R/0.48 (CHCI /MeOH 10 1)] into amine (Rf 0.21), and showed evidence of O- to JV-acetyl migration, but no evidence of an anomeric mixture. The catalyst was filtered off and washed with MeOH, and removal of the solvent gave the amine as colorless oil. The crude oil was used immediately for amino acid coupling. 

Urinary metabolites of acrylonitrile include 5 -(2-cyanoethyl)mercapturic acid, N-acet T-3-carboxy-5-cyanotctrahydro-I,4-3//-thiazine and thiocyanate (Kopecky et al., 1979 Langvardt et al., 1980 Gut c/ al., 1981 Sapota, 1982). The proportion excreted as thiocyanate by rats is far higher (23% of dose) after oral dosing than after intraperitoneal, intravenous or subcutaneous administration (1-4% of dose Gut et al., 1981). Other metabolites derived from the mercapturic acid pathway include. S -carboxymethylcys-teine,. S -hydroxyethylmercapturic acid [jV-acetyl-5 -(2-hydroxyethyl)cysteine] and thiodi-glycolic acid (Muller et al., 1987). 

After an oral dose of 6 mg/kg bw to rats, approximately 38% of the dose was exhaled as CO2, 50% was excreted as metabolites in the urine and 3% was present in faeces (Gingell et al., 1985). Concentrations were highest in liver, kidney and forestomach. The initial metabolic reactions are conjugation of the epoxide with glutathione, which is probably a chemical, not enzymatic, reaction, and hydration of the epoxide by epoxide hydrolase. The major metabolites in urine are jV-acetyl-5 -(3-chloro-2-hydroxypropyl)-L-cysteine (36% of the dose) and 3-chloro-1,2-propanediol (a-chlorohydrin) (4%). 

Page 124, line 17. For 1,3-di-JV-acetyl-2,4-di-0-acety 1- read 1,3-di-N-acetyl-4,6-di-0-acetyl-. ... 

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