Meso benzoyl chloride

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. ... 

The meso-ionic l,3-diazol-4-imine (98, R1 = R2 = Ph, R3 = Me, R4 = H, R3 = COPh) has been prepared60 from the nitrile (99, R3 = Me) and benzoyl chloride followed by treatment with sodium hydrogen carbonate. This compound (98, R1 = R2 = Ph, R3 - Me, R4 == H, R3 = COPh) undergoes a 1,3-dipolar cycloaddition with dimethyl acetylene-dicarboxylate in boiling benzene during 10 minutes, yielding the pyrrole... 

Oriyama was the first to provide a practical protocol for the ASD of this class of substrate [151-154]. Thus, employing just 0.5 mol% of (S)-proline-derived chiral diamine 36 in conjunction with benzoyl chloride as the stoichiometric acyl donor in the presence of Et3N, asymmetric benzoylation of a variety of meso-diols could be achieved with good to excellent enantioselectivities (66-96% ee) and >80% yields (Scheme 8.18). 

As mentioned earlier, meso-inositol, and indeed all the inositols, are readily converted to aromatic compounds by oxidation. Posternak found that inosose has the tendency to form phenolic compounds under very mild conditions. On attempted acetylation of inosose with acetic anhydride in the presence of either pyridine or sodium acetate the expected pentaacetate was not obtained the product was 1,2,3,5-tetra-acetoxybenzene (XXXVII). Similarly, the treatment of inosose pentaacetate with boiling acetic anhydride and pyridine or sodium acetate gave the same product. Inosose pentabenzoate was prepared by the use of benzoyl chloride and zinc chloride. Under the influence of pyridine or sodium acetate in acetic acid the pentabenzoate lost two molecules of benzoic acid to give l-hydroxy-2,3,5-tribenzoxybenzene (XXXVIII). 

Significantly improved results were obtained in 2003 by employing the phosphi-nite derivative 22 of cinchonine as a catalyst, which can be obtained as a mixture with the undesired corresponding phosphinate from the reaction of cinchonine (1) and chlorodiphenylphosphane [30a]. The desymmetrization reaction of a range of 1,2-meso-diols with benzoyl chloride in the presence of 30 mol% of the phosphinite 22 as a mixture containing about 15% phosphinate afforded the corresponding monobenzoylated diol in excellent yields and ee values (up to 94% ee) (Scheme 11.15). It was postulated by the authors that the reaction is initiated by the activation of the... 

The catalytic efficiency of the diamines, 24 and 25, derived from the truncated cinchona alkaloids, quincorine and quincoridine, respectively, for the desymmetrization of meso- 1,4-diols was also investigated by Kiindig and coworkers [31a, b[. Both pseudoenantiomers 24 and 25 efficiently catalyzed the desymmetrization of the meso-complex 26 with benzoyl chloride, giving the enantiopure monobenzoylated Cr (CO)3 complexes, 27 and ent-27, respectively, with up to 99% ee (Scheme 11.17). This process will provide easy access to new planar chiral complexes. 

Only the benzoyl chloride led to the meso-l-phenyl-2,5-divinyl-cyclopentanol... 

A number of general methods for the synthesis of meso-ionic 1,2,4-triazol-3-ones are available. Sodium ethoxide-catalyzed cyclization of 1-benzoyl-l,4-diphenylsemicarbazide (201, R = R = R = Ph, X = O) yielded anhydro-3-hydroxy-1,4,5-triphenyl-1,2,4-triazolium hydroxide (200, R = R = R = Ph). A general route to meso-ionic 1,2,4-triazol-3-ones (200) is exemplified by the formation of the 1,4,5-triphenyl derivative (200, R = R = R = Ph) from A-amino-MA -diphenylbenzamidine (202, R = R = R = Ph) and phosgene. In contrast with this ready meso-ionic compound formation, the corresponding reaction of the iV-methylbenzamidine (202, R = Me, R = R = Ph) did not yield the meso-ionic 1,2,4-triazol-3-one (200, R = Me, R = R = Ph). The product was in fact 3,4-diphenyl-2-methyl-l,2,4-triazol-5-onium chloride (203), which on heating gave 3,4-diphenyl-1,2,4-triazol-5-one (204, R = Ph). The formation of the A-methyl derivative (200, R = Me, R = R = Ph, yield 79%) by heating the 7V-thiobenzoyl semicarbazide (201, R = Me, R = R = Ph, X = S) with potassium carbonate in methyl cyanide has been reported. Another synthesis of A-methyl derivatives (200, R = Me) involves methylation of 3-methyl-4-phenyl-l,2,4-triazol-5-one (204,... 

The transformation 401 - 406 by Schotten-Baumann benzoylation is a mysterious reaction, the mechanism of which is not obvious. Clearly a change in oxidation level has occurred, but related changes are known, and this is an incompletely understood aspect of the chemistry of for-mazans (393) and the corresponding tetrazolium cations. In contrast, the reaction of the salt with p-toluenesulphonyl chloride yields the meso-ionic l,2,3,4-tetrazol-5-imine (411) directly. 

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