Benzoyl substituent

The bicyclic oxepin 8//-3-oxacyclohept[d]oxepin-8-one dissolved in trifluoroacetic acid undergoes a rearrangement to the expected phenol derivative 1. Substituents in the 2- and/or 7-position of the oxepin part, however, give rise to the formation of l-acylazulen-6-ols 2 by ring contraction.148 The 2,7-diphenyl derivative affords a mixture of l-benzoyl-2-phenylazulen-6-ol (37%), l-benzoyl-2-phenylazulen-6(l//)-one (35%), and 2-phenylazulen-6-ol (23%), which was presumably formed via the azulenone and a shift of the benzoyl substituent to the oxygen. 

For the synthesis of the target structures, it is absolutely necessary to introduce solubilizing substituents in the positions peripheral to the benzoyl substituents. The primary coupling product, 117, a poly(2,5-dibenzoyl-l,4-phenyl-ene) derivative - a poly(para-phenylene) with two benzoyl substituents in each structural unit - is, as expected, very poorly soluble. Highly substituted monomers (2,5-dibromo-l,4-bis(3,4-dihexyloxy-benzoyl)benzene), containing four solubilizing alkoxy groups per monomer unit, allow the synthesis of polymeric materials with M of about 12,000 and M, of about 22,000 [139]. 

An efficient synthesis of 2-amino derivatives 256 is depicted in Scheme 70 2-halopyridines are first Ar-alkylated with various halides under microwave activation and next reacted with cyanamide under basic conditions <1999T2317>. A rapid parallel synthesis of derivatives bearing a benzoyl substituent at C-3 based on this reaction has been described <2002SL1544>. 

New epibatidine analogues were characterized with the aid of one and two dimensional NMR techniques and IR, GC-MS spectroscopies (Fig. 38.1). All signals in the NMR spectra appeared in pairs due to the presence of rotamers that are resulted from the rotation between the unpaired electrons and benzoyl substituent on the nitrogen atom (Scheme 38.2). 

Diazomethane furnishes the methyl ether which has been degraded to 3-methoxyfuran which, however, is more easily available from 3-iodofuran. 3-Methoxyfuran is cleaved by acid to furan-3(2H)-one. Other 3-furanols with ester, acetyl or benzoyl substituents at the 2-position are also available. They exist in the enolic form but their chemistry has not been investigated (76JCS(P1)1688>. Furan-3(2H)-ones with acetyl or ester substituents at the 4-position are readily available. They exist in the keto form but show some evidence for enolic behaviour and their chemistry is similar to that of enolizable ketones. They enter into cycloaddition with maleic anhydride, are alkylated at the 2-position, condense with aldehydes and ketones and are oxidized by LTA to the 2-acetoxy compounds (74BSF2061). 

In 2-benzoyl-oxane (also in 2-benzoyl-thiane, -1,3-dithiane, 1,3-oxa-thiane) the benzoyl substituent adopts the equatorial conformation in the solid state (99IJC617). 

A novel pyrido[l,2-6]pyrrolo[2,3-e]-a -triazine (19) is produced when compound (15) is treated with ammonia ammonia attacks the C-lOa carbon and causes ring opening to give the triazinium derivative (18 Nu = NH2) and the amine substituent is then able to react with the carbonyl group of the benzoyl substituent to give the cyclized product (19) in high yield. 

There are occasions when the benzene ring is named as a substituent and in these cases the name for C Hj- is phenyl, abbreviated to Ph. The name for CgH5CH2- is benzyl or Bn, whilst the benzoyl substituent is CgHjCO- or Bz. These substituents can also be named systematically as shown in Figure 1.16. 

Azidonitration of the 5-thio-D-xylal 290 with sodium azide in acetonitrile and, subsequently with ceric ammonium nitrate, afforded a separable 1 1 mixture ofthe D-xylo (291) and the D-lyxo derivatives (292). " " They were converted into the corresponding 1-0-acetyl derivatives 293 and 294, on treatment with sodium acetate in acetic acid. In a similar way, azidonitration of 3,4-di-0-bcnzoyl-5-thio-D-ribal (295) afforded a mixture of the corresponding 2-azido-l-O-nilro derivatives that were converted, without separation, into the corresponding 1-O-acetyl derivatives, from which a 3 7 mixture of the a and anomers of 296 could be isolated in 72% y ield.- The steric arrangement of the axially oriented 3-0-benzoyl substituent in the erythro compoimd 295, which in compound 290 occupies an equatorial position, explains the differences found in the addition of the azido group at C-2 of both glycals. 

The photochemistry of 2-benzoylcyclohexanone and its 2-alkyl derivatives diverges. The unsubstituted compound undergoes ring cleavage, whereas the substituted compounds result in migration of the benzoyl substituent to the... 

Thus, the greatest disarming effect was seen from the 2-benzoyl substituent in compound 37, followed by the 4-benzoyl and 3-benzoyl substituents (in compounds 34 and 35, respectively). In addition, cyclic ketal 36 was found closer in reactivity to the mono-benzoylated rather than the di-benzoylated series of compounds. Not surprisingly, reactivity levels recorded for the mono-benzoylated (34, 35, 37), di-benzoylated (38-40), and torsionally disarmed (36) glycosyl donors fell in between the traditional per-benzylated armed rhamnoside 25 and its disarmed per-benzoy-lated counterpart 41. 

Reaction between heterocyclic aminals 84 with benzoyl substituents and various aryl azides in 1,4-dioxane at room temperature has been reported to give highly... 

Lam et al. synthesized isoxazolines 469 and pyrazolines 470 via monoalkylation with dimsyl anion and styrene oxide 480 and following an oxidation/ elimination strategy [292]. Oxidation of secondary alcohols 481 is performed via Jones oxidation and cyclization with cleavage from the resin follows in a separate step. Diverse elements can be introduced to the heterocycle using either hydroxylamine 483 or hydrazine derivatives 484 (Scheme 72). Corresponding six-membered heterocycles like pyridazine derivatives 471 can be obtained when the linked molecule 482 bears a benzoyl substituent instead of the phenyl substituent at the a-C-atom [293]. 

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