Biphenyl carbonyl

Sphingomyelin, bovine cerebrosides, psychosine and sphingo-sine were obtained from Supelco, Inc. Dihydrolactocerebroside and dihydroglucocerebroside were obtained from Miles Yeda Ltd. Psychosine and a new analog thereof were extracted from human brain tissue and separated by HPLC as their biphenyl carbonyl derivatives. 

Figure 7. Field desorption mass spectra recorded at 22—23 ma for a biphenyl carbonyl derivative of psychosine and a biphenyl carbonyl derivative of a new compound isolated from human brain tissue. Structure indicated for the unknown was assigned on the basis of this spectrum and chemical evidence relating the unknown to psychosine. Both samples were purified by HPLC prior to FDMS.

The intermolecular Diels-Alder reaction between the dibromoenone (111) and dienes (112) provides access to bicyclo[5.4.0]undecane systems (113) that are common core structures of many natural products (Scheme 32).118 The alio-threonine-derived O-(/ -biphenyl carbonyl oxy)-/i-phenyloxazaborolidi none catalyses the enan-tioselective Diels-Alder reaction of acyclic enones with dienes.119 The reversal of facial selectivity in the Diels-Alder cycloaddition of a semicyclic diene with a bro-moenone was induced by the presence of the bromo substituent in the dienophile.120 Mixed Lewis acid catalyst (AlBr3/AIMe3) catalyses the Diels-Alder reaction of hindered silyloxydienes with substituted enones to produce highly substituted cyclohexenes.121 Chiral /V-enoyl sultams have been used as chiral auxiliaries in the asymmetric Diels-Alder reactions with cyclopentadiene.122... 

Fig. 2. High-performance liquid chromatographic analysis of biphenyl-carbonyl derivative of psychosine standards obtained by cerebroside hydrolysis, f represents point of injection. Abbreviation S.F.= sol-vent front.

Inhibitors for proteases plasmepsin I and II of the malaria parasite Plasmodium falciparum, with a good plasmepsin/human protease cathepsin D selectivity, have been identified via library construction involving rapid microwave-accelerated Suzuki reactions [57]. The phenyl ring of the biphenyl unit in the lead compound M-((lS)-l- [((lS,2S)-3- [(lS)-2-amino-l-(4-phenyl-benzyl)-2-oxoethyl]amino -2-hydroxy-l-phenoxypropyl)amino]carbonyl -2-methylpropyl)pyridine-2-carboxamide has been altered by performing Suzuki reactions on N-((lS)-l- [((lS,2S)-3- [(lS)-2-amino-l-(4-bromobenzyl)-2-oxoethyl]amino -2-hydroxy-l-phenoxypropyl)amino]carbonyl -2-methyl-propyl)pyridine-2-carboxamide (Scheme 37). In particular, a 2-benzofuryl moiety proved to be interesting since a Ki value of 13 nM for plasmepsin I and... 

On page 132, atropisomerism was possible when ortho substituents on biphenyl derivatives and certain other aromatic compounds prevented rotation about the bond. The presence of ortho-substituents can also influence the conformation of certain groups. In 88, R= alkyl, the carbonyl unit is planar with the trans C=0 - F conformer more stable when X=F. When X=CF3, the cis and trans are planar and the trans predominates. When R = alkyl there is one orthogonal conformation but there are two interconverting nonplanar conformations when R=0-alkyl. In 1,2-diacylbenzenes, the carbonyl units tend to adopt a twisted conformation to minimize steric interactions. " ... 

CN ( )-2-ethoxy-l-[[2 -(l/7-tetrazol-5-yl)[l,r-biphenyl]-4-yl]methyl]-lW-benzimidazole-7-carboxylic acid l-[[(cyclohexyloxy)carbonyl]oxy]ethyl ester... 

Hori and her collaborators [157, 158] also investigated the crystal structures of 4-[(S)-l-methyl-pentyloxycarbonyl]phenyl 4 -octyloxybiphenyl-4-carboxyl-ate, 4- [ (S)-1 -methyl-hexyloxy-carbonyl] phenyl 4 -octyloxybiphenyl-4-carbox-ylate, and (R)-l-methylheptyl 4-(4 -octyloxy-biphenyl-4-yloxymethylene) benzoate. All three crystal structures are isomorphous with the structure of MHPOBC. 

The reaction of biphenyl with formic acid and K2S208 in a mixture of GF3C02H and GH2G12, using Pd(OCOCF3)2 as a catalyst, gives hydroxyl-biphenylcarboxylic acid in 45% yield (Equation (76)).101 The hydroxylation and carboxylation proceeds on one molecule. This reaction is applied to the palladium-catalyzed carboxylation of benzenes using formic acid as a carbonyl source. 

Along with the prediction and discovery of a macroscopic dipole in the SmC phase and the invention of ferroelectric liquid crystals in the SSFLC system, the discovery of antiferroelectric liquid crystals stands as a key milestone in chiral smectic LC science. Antiferroelectric switching (see below) was first reported for unichiral 4-[(l-methylheptyloxy)carbonyl]phenyl-4/-octyloxy-4-biphenyl carboxylate [MHPOBC, (3)],16 with structure and phase sequence... 

The idea of enantioselective activation was first reported by Mikami and Matsukawa111 for carbonyl-ene reactions. Using an additional catalytic amount of (R)-BINOL or (/ )-5.5 -dichloro-4,4, 6,fi -tctramcthyl biphenyl as the chiral activator, (R)-ene products were obtained in high ee when a catalyst system consisting of rac-BINOL and Ti(OPri)4 was employed for the enantioselective carbonyl ene reaction of glyoxylate (Scheme 8-54). Amazingly, racemic BINOL can also be used in this system as an activator for the (R)-BINOL-Ti catalyst, affording an enhanced level of enantioselectivity (96% ee). 

The benzanthrone system is susceptible to both electrophilic and nucleophilic attack. The most reactive sites towards electrophiles are the 3- and 9-positions, which can be compared with the 4,4 -positions in biphenyl. The 9-position is somewhat deactivated by the carbonyl group, however. Thus, for example, monobromination takes place at the 3-position and further substitution gives 3,9-dibromobenzanthrone. Nitration and benzoylation similarly give rise to the 3-substituted product. The 3-position is in fact peri-hindered (compare naphthalene) so that sulphonation yields the 9-sulphonic acid. Electron withdrawal by the carbonyl group activates the 4- and 6-positions towards nucleophilic attack for example, hydroxylation occurs at these sites. 

SOCl2 (208 g, 1.75 mol) is added in one portion to a refluxing solution of TEBA-Cl (0.27 g, l. 2 mmol) and the acid (0.826 mol) in Cl(CH2)2Cl (l. 5 l). The solution is refluxed for a further period of time, and then filtered hot and evaporated to yield the acid chloride, which is purified, if necessary, by chromatography from silica [e.g. trans-cyclohexane-1,4-dicarbonyl chloride (30 min), 96% naphthalene-2,6-dicarbonyl chloride (12 h), 94% biphenyl-4-carbonyl chloride (25 min), 60% biphenyl-4,4 -dicarbonylchlo-ride (16 h), 90%]. 

This type of isomerism is possible not only in biphenyls, but also in compounds in which rotation about an sp2-sp2 bond is restricted and the two planes involving the sp2 center are noncoincident and substituted unsymmetrically. In addition to enantiomers, diastereomers are possible. There are some examples reported of restricted rotation about an aromatic ring-to-carbonyl bond or aromatic ring-to-nitrogen bond (28). Since these reports make no mention of diastereomers but only of enantiomers, they will receive no further mention here. 

Binaphthol- and biphenyl-derived ketones (9 and 10) were reported by Song and coworkers in 1997 to epoxidize unfunctionalized alkenes in up to 59% ee (Fig. 3, Table 1, entries 9, 10) [37, 38]. Ketones 9 and 10 were intended to have a rigid conformation and a stereogenic center close to the reacting carbonyl group. The reactivity of ketones 9 and 10 is lower than that of 8, presumably due to the weaker electron-withdrawing ability of the ether compared to the ester. In the same year, Adam and coworkers reported ketones 11 and 12 to be epoxidation catalysts for several trans- and trisubstituted alkenes (Table 1, entries 11,12). Up to 81% ee was obtained for phenylstilbene oxide (Table 1, entry 25) [39]. 

Carbonylative coupling reaction of Ar3Bi and carbon monoxide takes place under rhodium catalysis (Scheme 46) [61, 62]. Ph3Bi reacted with carbon monoxide in the presence of 5 mol% of [RhCl(CO)2]2 in MeCN at room temperature to give benzophenone in 71% yield together with a small amount of biphenyl. The same... 

The synthesis of acrylic acid or its ester (228) from ethylene has been investigated in AcOH from the standpoint of its practical production 12]. The carbonylation of styrene is a promising commercial process for cinnamate (229) production[207,213,214]. Asymmetric carbonylation of styrene with Pd(acac)2 and benzoquinone in the presence of TsOH using 2,2 -dimethoxy-6, 6 -bis(diphenylphosphino)biphenyl (231) as a chiral ligand gave dimethyl phenylsuccinate 230 in 93% ee, although the yield was not satisfactory, showing that phosphine coordination influences the stereochemical course of the oxidative carbonylation with Pd(II) salt[215]. 

The catalytic asymmetric epoxidation of a,/i-unsaturated carbonyl compounds is one of the synthetically useful reactions in organic synthesis.The resulting chiral epoxides are easily converted to various useful chiral compounds. We developed a new yttrium-(5)-6,6 -[oxybis(ethylene)dioxy]biphenyl-2,2 -diol (1) (Figure 6.10)... 

Naphthalenes biphenyls.3 The reaction of 1,3-diphenylacetone (1) with DMF dimethyl acetal at 110° affords the bisenamine 2 when conducted at 180° the reaction results in a naphthalene derivative (3) (equation I). This synthesis of naphthalenes is general and yields are usually 50-90%. The same reaction when applied to 4 results in a 4-methoxybiphenyl derivative (5) (equation II). When the carbonyl group in 1 is labeled with 13C, it can be identified as the carboxyl group in the carboxamide 3. Thus an extensive rearrangement is involved. 

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