4-acyl-2-acylamino

Oxo-l-propenylamino)-l,2,4-oxadiazole lagern sich mit Natriumethanolat in Dimethyl-formamid in Ausbeuten von 60-80% in 4(5)-Acyl-2-acylamino-imidazole um392 ... 

Azlactones (anhydrides of a-acylamino acids) are formed by the condensation of aromatic aldehydes with acyl derivatives of glycine in the presence of acetic anhydride and anhydrous sodium acetate. Thus beiizaldehyde and acetyl-... 

The reactivity of the 5-acyl group of 2-acylamino-5-acylthiazole in the formation of Mannich bases is greater than that observed for 2-amino-5-acylthia2ole (476). 

A further group of whiteners was found in the acylamino (R,R ) derivatives (16) of 3,7-diaminodibenzothiophene-2,8-disulfonic acid-5,5-dioxide. The preferred acyl groups are aLkoxybenzoyls (72—74). These compounds give a greenish fluorescence and are relatively weak in comparison with stilbene derivatives on cotton however, they show good stabiUty to hypochlorite. 

AH cephalosporins found in nature (Tables 1 and 2) have the D-a-aminoadipic acid 7-acyl side chain (21). AH of these compounds can be classified as having rather low specific activity. A substantial amount of the early work in the cephalosporin area was unsuccessfiiHy directed toward replacing the aminoadipic acid side chain or modifying it appropriately by fermentation or enzymatic processes (6,22). A milestone ia the development of cephalosporins occurred in 1960 with the discovery of a practical chemical process to remove the side chain to afford 7-ACA (1) (1). Several related processes were subsequendy developed (22,23). The ready avaHabHity of 7-ACA opened the way to thousands of new semisynthetic cephalosporins. The cephalosporin stmcture offers more opportunities for chemical modification than does that of penicillins There are two side chains that especiaHy lend themselves to chemical manipulation the 7-acylamino and 3-acetoxymethyl substituents. 

Chemical Modification. The chemistry and synthetic strategies used in the commercial synthesis of cephalosporins have been reviewed (87) and can be broadly divided into ( /) Selection of starting material penicillin precursors must be rearranged to the cephalosporin nucleus (2) cleavage of the acyl side chain of the precursor (2) synthesis of the C-7 and C-3 side-chain precursors (4) acylation of the C-7 amino function to introduce the desked acylamino side chain (5) kitroduction of the C-3 substituent and 6) protection and/or activation of functional groups that may be requked. 

Benzo[6]thiophene, 2-acetyl-3-hydroxy-synthesis, 4, 892 Benzo[6]thiophene, 2-acyl-synthesis, 4, 918 Benzo[6]thiophene, 3-acyl-synthesis, 4, 918- 19 Benzo[6]thiophene, acylamino-synthesis, 4, 815 Benzo[6]thiophene, alkenyl-synthesis, 4, 917 Benzo[6]thiophene, 2-alkoxy-synthesis, 4, 929 Benzo[6]thiophene, 3-alkoxy-synthesis, 4, 929 Benzo[6]thiophene, 4-alkoxy-synthesis, 4, 930 Benzo[6]thiophene, 2-alkyl-synthesis, 4, 877-878 Benzo[6]thiophene, 2-alkylthio-synthesis, 4, 931 Benzo[6]thiophene, 2-amino-diazotization, 4, 810 reactivity, 4, 797 stability, 4, 810 synthesis, 4, 869, 924-925 tautomerism, 4, 38 Benzo[6]thiophene, 3-amino-cycloaddition reactions, 4, 68 synthesis, 4, 109, 881, 925 Benzo[6]thiophene, 4-amino-synthesis, 4, 925 Benzo[6]thiophene, 5-amino-synthesis, 4, 925 Benzo[6]thiophene, 7-amino-synthesis, 4, 925 Benzo[6]thiophene, 3-t-amyl-synthesis, 4, 915 Benzo[6]thiophene, 2-aryl-synthesis, 4, 881... 

Furan, 3-acetyl-5-(hydroxymethyl)-2-methyl-synthesis, 4, 663 Furan, 2-acyl-synthesis, 4, 148, 690 Furan, 3-acyl-synthesis, 4, 662, 670 Furan, 4-acyl-2-alkyl-synthesis, 4, 688 Furan, 3-acylamino-tautomerism, 4, 38... 

In their acidity, basicity, and the directive influence exerted on electrophilic substitution reactions in benzenoid nuclei, acylamino groups show properties which are intermediate between those of free amino and hydroxyl groups, and, therefore, it is at first surprising to find that the tautomeric behavior of acylaminopyridines closely resembles that of the aminopyridines instead of being intermediate between that of the amino- and hydroxy-pyridines. The basicities of the acylaminopyridines are, indeed, closer to those of the methoxy-pyridines than to those of the aminopyridines, the position of the tautomeric equilibrium being determined by the fact that the acyl-iminopyridones are strong bases like the iminopyridones and unlike the pyridones themselves. Thus, relative to the conversion of an... 

Acyl-l //-1,2-diazepines 2 isomerize on heating above 150 C to the corresponding pyridine l-imines 67c in certain cases 1,3-diazepines arc also formed (see Section 4.1.3.2.1.1.1.). These products are accompanied by variable amounts of pyridine and 2-(acylamino)pyridines. 

Also the scope of the acylase method is limited in practice because chemical acylation of amino adds is difficult, and some N-acylamino adds are unsusceptible to the enzyme. 

Acetamino-methyl- -athylester-nitril 206 Acylamino- -diathylester 203 Acyl- -diathylester... 

Addition of an acyl group and an acylamino group to a double bond... 

The choice of the acyl substituent X for Diels-Alder reactions of l-N-acylamino-l,3-butadicnes depends on the particular synthetic problem. The acyl substituent has a moderate effect on the cycloaddition reactivity of these dienes, and also determines what amine unmasking procedures are required. As a result of their stability and the variety of amine deprotection procedures available, " the diene carbamates are the components of choice in most cases. A particularly attractive aspect of the diene synthesis detailed here is the ability to tailor the amino-protecting group... 

The reaction of 3,4-diacyl-l,2,5-oxadiazole 2-oxides (furoxans) with activated nitriles in ionic liquids and in ethanol unexpectedly resulted in 3-acyl-4-acylamino-l,2,5-°xadiazoles (furazans) <2003MC230>. 3-Formyl-4-phenyl-l,2,5-oxadiazole Ar-oxide 105 is a good precursor for the synthesis of functional substituted furoxans (Scheme 28) <1999JME1941, 2000MOL520, 2000JFA2995>. 

The reactions of Meldrum s acid (421) and acyl isothiocyanates in DMSO in the presence of lithium hydride at ambient temperature for 2-3 hr gave the lithium salts (457), which were alkylated by treatment with alkyl halide for 5 hr to afford isopropylidene (acylamino)(alkylthio)methy-lenemalonates (458) in 20-90% yields (87ZC68). 

Hybrid pseudolipid analogues such as l,3-bis(acylamino)prop-2-yl esters (RCONHCH2-CH(OCOR )-CH2NHCOR), where R is a fatty acyl substituent and OCOR is the active carboxylate moiety. 

Nohira et al. treated N-acylamino acids 195 with thionyl chloride mixed anhydrides 196 were formed below 30°C. The latter compounds gave the first type of hexahydro-2//-3,l-benzoxazin-4-one 197 on triethylamine treatment [77H(7)301]. This reaction was also performed with diexo- and diendo-substituted j8-amino acids 198 yielded the 5,8-methano-2//-3,l-benzoxazin-4-ones 199 via the acyl derivatives 200 (84S345,84T2385). Further homologs were also prepared by the dehydration of N-acylamino acid derivatives (85MI1 88MI3). 

German workers have prepared a very large number of 4-acyl-2-acylamino-4,5-dihydro-l,3,4-thiadiazoles (138) by the condensation of substituted thiosemicarbazones with acid chlorides (Equation (15)) <86JPR205>. 

A general synthetic route to meso-ionic iV-acyl-l,3-thiazol-5-imines (108, R = Ph, = Me, R = Me or Ph, R = COPh) is provided by treatment of thiobenzamidoaminoacetonitriles, Ph-CS-NMe-CHR-CN, first with benzoyl chloride and then with aqueous alkali. Alternatively, the thiobenzamidoaminoacetonitriles and hydrogen chloride give the corresponding salts, which with benzoyl chloride and aqueous alkali give -acyl l,3-thiazol-5-imines Derivatives (108, R = SMe) have been obtained by treating 5-acylamino-4-thiazoline-2-thiones with methyl iodide and aqueous alkali. ... 

Silyl-substituted diazoketones 29 cycloadd with aryl isocyanates to form 1,2,3-triazoles 194 (252) (Scheme 8.44). This reaction, which resembles the formation of 5-hydroxy-l,2,3-triazoles 190 in Scheme 8.43, has no analogy with other diazocarbonyl compounds. The beneficial effect of the silyl group in 29 can be seen from the fact that related diazomethyl-ketones do not react with phenyl isocyanate at 70 °C (252). Although the exact mechanistic details are unknown, one can speculate that the 2-siloxy-1-diazo-1-alkene isomer 30 [rather than 29 (see Section 8.1)] is involved in the cycloaddition step. With acyl isocyanates, diazoketones 29 cycloadd to give 5-acylamino-l,2,3-thiadiazoles 195 by addition across the C=S bond (252), in analogy with the behavior of diazomethyl-ketones and diazoacetates (5). 

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