Acetic acid, acetamide prepared from

The A-substituted derivatives of 4-oxo-4//-pyrido[l,2-n]pyrimidine-3-carboxamides and -3-acetamides and l,6-dimethyl-4-oxo-1,6,7,8-tetrahy-dro-4//-pyrido[l,2-n]pyrimidine-3-carboxamide were prepared by treatment of the appropriate 3-carboxylic acids and acetic acid, first with an alkyl chloroformate in the presence ofNEt3 in CHCI3 below — 10°C, then with an amine (98ACH515). A-Phenethyl and A-[2-(3,4-dimethoxyphenyl)ethyl] derivatives of 6-methyl-6,7,8,9-tetrahydro-4//-pyrido[l, 2-n]pyrimidine-3-acetamide were obtained in the reaction of 6-methyl-6,7,8,9-tetrahydro-4//-pyrido[l,2-n]pyrimidine-3-acetic acid and phenethylamines in boiling xylene under a H2O separator. Hydrazides of 4-oxo-4//- and 4-oxo-6,7,8,9-tetrahydro-4//-pyrido[l, 2-n]pyrimidine-3-acetic acid were prepared from the appropriate ester with H2NNH2 H2O in EtOH. Heating 4-oxo-4//- and 6-methyl-4-oxo-6,7,8,9-tetrahydro-4//-pyrido[l, 2-n]pyrimidine-3-acetic hydrazides in EtOH in the presence of excess Raney Ni afforded fhe appropriafe 4-oxo-6,7,8,9-fefrahydro-4//-pyrido[l,2-n]pyrimidine-3-acefa-mide. In the case of the 4-oxo-4// derivative, in addition to N-N bond... 

The variety of educts and products of the higher MCRs is illustrated here. Product 72 (Scheme 1.18) is formed from the five functional groups of lysine, benzaldehyde, and tert-butylisocyanide. The synthesis of 73 is achieved with hydrazine, furanaldehyde, malonic acid, and the isocyano methylester of acetic acid, compound 74 results from the reaction of benzylamine, 5-methyl-2-furanaldehyde, maleic acid mono-ethylester, and benzylisocyanide. ° Zhu et al. prepared a variety of related products, such as, 75, from (9-amino-methyl cinnamate, heptanal, and a-isocyano a-benzyl acetamides. 

The energetic nitramide (60) has been prepared from the nitration of the tris-acetamide (59) with nitric acid and acetic anhydride or trifluoroacetic anhydride. Nitric acid-trifluoroacetic anhydride mixtures are powerful nitrating agents and well suited for amide and urea A-nitration. 

A typical example that illustrates the method concerns the lipase- or esterase-catalyzed hydrolytic kinetic resolution of rac-1-phenyl ethyl acetate, derived from rac-1-phenyl ethanol (20). However, the acetate of any chiral alcohol or the acetamide of any chiral amine can be used. A 1 1 mixture of labeled and non-labeled compounds (S)- C-19 and (f )-19 is prepared, which simulates a racemate. It is used in the actual catalytic hydrolytic kinetic resolution, which affords a mixture of true enantiomers (5)-20 and (J )-20 as well as labeled and non-labeled acetic acid C-21 and 21, respectively, together with non-reacted starting esters 19. At 50% conversion (or at any other point of the kinetic resolution), the ratio of (5)- C-19 to (1 )-19 correlates with the enantiomeric purity of the non-reacted ester, and the ratio of C-21 to 21 reveals the relative amounts of (5)-20 and (J )-20 (98). 

Benzhydryl 7-amino-3-chloromethyl-3-cephem-4-carboxylate (2.29 g) was treated with bis(trimethylsilyl)acetamide (4.06 ml) at room temperature for 50 min to give a clear solution. Top the solution was added an acid chloride solution, which was prepared from (Z)-2-hydroxyimino-2-(2-tritylaminothiazol-4-yl)acetic acid (2.04 g) and PCI5 (1.15 g) in methylene chloride (20 ml). The mixture was stirred at room temperature for 30 min, poured in cold water (200 ml) and extracted with ethyl acetate (100 ml x 3). After evaporation of the solution was obtained the syrup (4 g) which was chromatographed on a silica gel column by eluting with 10 1 and 3 1 mixture of toluene and ethyl acetate successively. After evaporation of the solvents was obtained benzhydryl 3-chloromethyl-7-[(Z)-2-methoxyimino-2-(2-tritylaminothiazol-4-yl)acetamido]-3-cephem-4-carboxylate (2.62 g, 68%). 

The reductive cyclization of 2-nitrobenzyl-A, A -bis(formamide) with zinc in acetic acid to quinazoline was first described by RiedelT ° The reaction is used successfully for the synthesis of larger quantities of quinazoline and its benzene-ring-substituted derivatives 12 from 2-ni-trobenzyl-A, A -bis(formamides) 11. The method is suitable only for the preparation of 4-un-substituted quinazolines, because 2-nitro-substituted phenones do not condense with aliphatic amides to yield bis(amide) derivatives. Zinc in acetic acid is the reducing agent of choice, but iron in hydrochloric acid or Raney nickel can also be used. " Applications of compounds other than bis(formamides) [e.g., bis(acetamides) ] and preparation of 2-substituted quinazolines by Riedel s synthesis are scarce. 

Even though formic anhydride is not a stable compound (see p. 723), amines can be formylated with the mixed anhydride of acetic and formic acids (HCOO-COMe) or with a mixture of formic acid and acetic anhydride. Acetamides are not formed with these reagents. Secondary amines can be acylated in the presence of a primary amine by conversion to their salts and addition of 18-crown-6. The crown ether complexes the primary ammonium salt, preventing its acylation, while the secondary ammonium salts, which do not fit easily into the cavity, are free to be acylated. Dimethyl carbonate can be used to prepare methyl carbamates in a related procedure. A-Acetylsulfonamides were prepared from acetic anhydride and a primary sulfonamide, catalyzed by Montmorillonite KlO-FeO or sulfuric acid. "... 

Acetic anhydride is often used to prepare acetate esters from alcohols and AT-substituted acetamides from amines. For example, aspirin (acetyl-salicylic acid) is prepared commercially by the acetylation of o-hydroxy-benzoic acid (salicylic acid) with acetic anhydride. Acetaminophen, a drug used in over-the-counter analgesics such as Tylenol, is prepared by reaction of p-hydroxyaniline with acetic anhydride. Note that the more nucleophilic -NH2 group reacts, rather than the less nucleophilic -OH group. 

In the case of ammonia, acetamide is formed the product with aniline is acetanilide, The second substance formed is the aniline salt of acetic acid this is soluble in water and is readily removed when the product of the reaction is crystallized. The preparation of anilides in this way from acid anhydrides is often effected in the identification of anhydrides. The anilides are solids, which can be readily purified as a consequence, an identification can be accomplished with a very small amount of a substance. 

The classical dehydration of ammonium acetate to acetamide is accelerated by acetic acid, consequently the usual procedure for the preparation of acetamide involves careful distillation of an ammonium acetate-acetic acid mixture. The distillate is a solution of acetic acid and water. Finally excess acetic acid is distilled out followed by acetamide (yield 87-90% of theory, mp SrC). The product may be recrystallized from a benzene-ethyl acetate mixture [1]. 

B. H-(2,4-Diformyl-S-hydroxyphenyl)acet amide. A suspension of 95 g of the phenol (prepared under Section A) (Note 6) in 1 L of aqueous 10% hydrochloric acid is stirred for 2 hr at room temperature. The colorless solid (Note 7) is filtered by suction and twice suspended in water at 40°C. Final filtration is followed with a water wash (1 L, 40°C), and the solid is sucked down on the filter. Crystallization from 800 mL of acetonitrile affords 21.8-22.3 g (66-67.5%) of TV-(2,4-diformyl-5-hydroxyphenyl)acetamide, mp 215-217°C (Note 8). 

We have found that the reaction between tr iethylor tho-acetate and excess piperidine or morpholine with acidic catalysis is not an equilibrium reaction. Ethanol generated need not be removed as it forms. Additionally, 1WR studies indicate that at 100°C the preparative reaction is ccnplete in 10 to 20 minutes with little or no substituted acetamide side products formed. Hie stability of these ccnpounds in the presence of alcohol and/or excess amine contrasts the behavior of ketene acetals which revert rapidly to orthoesters in the presence of alcohol. This of course speaks to the utility of these various compounds in the presence of hydroxyl functionalities from either RIM polyols or RIM glycol ooextenders. 

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