Bleeding tendency IP 121/ASTMD 1742  [c.310]

Fig. 12.20 4-Acetamido benzoic acid. Triangle smoothing predicts that the lower bound distance between the amide nitrogen and the carbonyl oxygen is equal to the sum of the van der Waals radii. The actual distance is about 6.4A. Fig. 12.20 4-Acetamido benzoic acid. Triangle smoothing predicts that the lower bound distance between the amide nitrogen and the carbonyl oxygen is equal to the sum of the van der Waals radii. The actual distance is about 6.4A.
Met hy 1-5- [iV-(2-propeny 1)-acetamido]-7-benzyloxy TsOH, THF 90 [4]  [c.60]

H transfer from the methyl to the exocyclic nitrogen of the acetamido group.  [c.28]

With the more acidic 2-acetamido-4-R-thiazoles. using the weaker base NaOH as condensation agent, a mixture of ring (45) and exocyclic N-alkylation (46) may be observed (Scheme 33) (121). Reaction of 2-acetamido-4-methylthiazole in alcoholic sodium ethoxide solution with a variety of alkylating agents has been reported (40-44).  [c.35]

Boiling acetic acid converts 2-aminothiazole into the 2-acetamido derivative far more easily when catalytic amounts of diketene are added to the reaction mixture (277),  [c.53]

When the 5-position is occupied, as in 2-acetamido-5-methylthiazole (182), small amounts of 4-nitration are observed (Scheme 116) (27).  [c.74]

Acetamido-4-methylthiazole does not react with acetyl chloride in the Friedel-Crafts reaction (172. 407, 449).  [c.80]

Sulphanilamide, the simplest member of a large series of bacteriostatic drugs, can readily be prepared by the following reactions. Acetanilide, when treated v ith an excess of chlorosulphonic acid, gives p-acetaniidobenzencsulphonyl chloride (Reaction A), w hich readily reacts with ammonia to give p-acetamido-benzenesulphonamide (Reaction H). The acetamido-group in the latter  [c.181]

Tandem cyclization/3-substitution can be achieved starting with o-(trifluoro-acetamido)phenylacetylenes. Cyclization and coupling with cycloalkenyl trif-lates can be done with Pd(PPh3)4 as the catalyst[9]. The Pd presumably cycles between the (0) and (II) oxidation levels by oxidative addition with the triflate and the reductive elimination which completes the 3-alkenylation. The N-protecting group is removed by solvolysis under the reaction conditions, 3-Aryl groups can also be introduced using aryl iodides[9].  [c.23]

Acetamido-2-(7-chloroindol-3-ylmethyl)propanedioic acid dimethyl ester[6]  [c.62]

One effective method for synthesis of tryptophan derivatives involves alkylation of formamido- or acetamido- malonate diesters by gramine[l,2]. Conversion to tryptophans is completed by hydrolysis and decarboxylation. These reactions were discussed in Chapter 12. An enolate of an a-nitro ester is an alternative nucleophile. The products can be converted to tryptophans by rcduction[3,4],  [c.129]

Methyl 1 -(4-methylpheny sulfonyl)indo e-4-fa -acetamido)propenoate[2]  [c.143]

Reduction of 2.4-dimethyl-5-nitrothiazole with activated iron gives a product that after acetylation yields 25% 2.4-dimethyl-5-acetamido-thiazole (58). The reduction of 2-methyl 5-nitrothiazole is also reported (351 to give a mixture of products. The nitro group of 2-acetylhydrazino-5-nitrothiazole is reduced by TiCl in hydrochloric acid or by Zn in acetic acid (591.  [c.16]

An intramolecular charge transfer toward C-5 has been proposed (77) to rationalize the ultraviolet spectra observed for 2-amino-5-R-thiazoles where R is a strong electron attractor. Ultraviolet spectra of a series of 2-amino-4-p-R-phenylthiazoles (12) and 2-amino-5-p-R-phenylthiazoles (13) were recorded in alcoholic solution (73), but, reported in an article on pK studies, remained undiscussed. Solvent effects on absorption spectra of 2-acetamido and 2-aminothiazoles have been studied (92).  [c.21]

The fragmentation patterns of 2-acetamido-5-nitrothia2oie (17) and 2-diraethylaminothiazole are reported to be characterized by the stabilization brought by the amino group to the thiazole ring (137). The proposed fragmentation scheme (Scheme 19) displays two major features,  [c.28]

During the course of biochemical studies (138). the mass spectrum of 2-acetamidothiazole was recorded its main peaks are the molecular ion (m/e= 142, relative intensity = 26%) and fragments 100 (100), 58 (2. 5), and 43 (39). For 2-acetamido-5-bromothiazole the main peak results again from the loss of C2H2O by the molecular ion. 2-AcetyIacet-amido-4-methylthiazole (2S) exhibits significant loss of from the  [c.29]

An alkyi group occupying the 4-position of the thiazole ring may condense if the 5-position is substituted. 2-Acetamido-4-methy]-5-nitrothiazole (80) and p-cyanobenzaldehyde when refluxed with small amounts of piperidine yield the 4-styryl derivative (81) (Scheme 57) (238, 239).  [c.46]

Acetylation of 2-phenyl-4-amino-5-benzoylthiazole takes place on the exocyclic nitrogen (49). This exocyclic nitrogen remains the reactive center even with 2-imino-3-aryl-4-amino-5-carboxamido-4-thiazoline (111). Its acetylation with acetic anhydride gives the 4-acetamido derivative (112), which reacts further on heating to yield 2-(acetylimino)-(3H)-3-aryl-5-methylthiazolo[4,5-d]pvrimidin-7-(6H)-one (113) (Scheme 76) (276).  [c.53]

Acetamidothiazole is nitrated in the same way (58, 378, 379). 2-Acetamido-4-phenylthiazole is reported to be nitrated on C-5 (380) as opposed to 2-amino-4-phenylthiazole, where nitration occurs on the phenyl ring (381). This latter result is not consistent with the other data on electrophilic reactivity in most cases 2-amino-4-arylthiazole derivatives react with electrophilic reagents at the C-5 position (see Sections rV.l.B and D). Furthermore, N-pyridy]-(2)-thiazolyl-2-amine (178) is exclusively nitrated on the thiazole ring (Scheme 113) (132, 382).  [c.72]

Acetamidothiazole and its 4-alkyl derivatives react with chloro-sulfonic acid. The structure of the resulting products was a subject of controversy (172. 393-397). N-acetyl-A -(2-thiazolyl)-sulfamoyl chlorides (189) first proposed were then shown to be 2-acetamido-5-chloro-sulfonylthiazoles (190) (Scheme 120) (367. 368. 398). the latter assignment is based on infrared (368) and chemical evidence (367).  [c.75]

Acetamido-4-methy)thiazole when enzymatically brominated is converted to a mixture of 2-acetamido-4-methyd 5-bromothiazole (200) and dibromacetamido-4-methyl-5-bro mo thiazole (201) (Scheme 127) (138, 436).  [c.79]

Mercuric acetate heated for 18 hr at 100°C in acetic acid with 2-acetamidothiazole yields 2-acetamido-4,5-diacetoxymercurithiazole (214) (396). This product may then be transformed to the 4.5-diiodo derivative of 2-acetamidothiazole (215) (Scheme 135).  [c.82]

These compounds are easily prepared from the appropriate 2-aminothiazole and acyl chloride (see Section III.2.D) or by general heterocydization methods. Acyl chlorides may be replaced by the corresponding anhydrides (471). Acids themselves may be used as acylating agents provided that the imidazole-triphenyl phosphine mixture is used as a catalyst (472). The Curtius degradation of 247 yields 2-acetamido-4-phenylthiazole (248) (Scheme 149) (473).  [c.90]

Differences of electronic effect between 2-amuio and 2-acetamido substituents are also illustrated by  [c.91]

A protomeric equilibrium favors the acetamido rather than the acetimido form (105, 121). The parent molecular ion has been reported to be absent in the mass spectrum of 2-acylaminothiazoles (130).  [c.91]

The general pattern of alkylation of 2-acylaininothiazoles parallels that of 2-aminothia2ole itself (see Section III.l). In neutral medium attack occurs on the ring nitrogen, and in alkaline medium a mixture of N-ring and N-amino alkylation takes place (40, 43, 161. 163). In acidic medium unusual behavior has been reported (477) 2-acetamido-4-substituted thiazoles react with acetic anhydride in the presence of sulfuric acid to yield 2-acetylimino-3-acetyl-4-phenyl-4-thiazolines (255) when R = Ph. but when R4 = Me or H no acetylation occurs (Scheme 151). The explanation rests perhaps in an acid-catalyzed heterocyclization with an acetylation on the open-chain compound (253), this compound being stabilized  [c.91]

Sulfenamidothiazoles heated in acetic anhydride rearrange to 2-acetamido-5-thiophenoxythicLZoles (337) (Scheme 193) (32, 456, 457). Only decomposition products are found when these conditions are applied to 336 with X=C or methyl. Substitution in the 4-position of the thicLZole ring (R = methyl, phenyl), however, favors the rearrangement (see p. 82).  [c.114]

Acetamido-4-methyl-5-thiazolyl-sulfuryl chloride gives by hydrolysis the acid, which on heating with H2SO4 is reported to give the 2-sulfamic acid (337).  [c.414]

Chloro- and 2-acetamido-5-sulfide derivatives are readily oxidized to the corresponding sulfones, while curiously enough 2-hydroxy-5-arylsulfides are reported to be stable to oxidation (228, 55 )-  [c.415]

See pages that mention the term Austamide : [c.50]    [c.164]    [c.379]    [c.22]    [c.676]    [c.546]    [c.1006]    [c.1009]    [c.181]    [c.548]    [c.62]    [c.33]    [c.44]   
The logic of chemical synthesis (1989) -- [ c.396 ]