Kiminori Tomimatsu

Practical synthesis of (R)-(+)-6-(1,4-dimethoxy-3-methyl-2-naphthyl)-6-(4-hydroxyphenyl)hexanoic acid: a key intermediate for a therapeutic drug for neurodegenerative diseases

Abstract A practical method for the preparation of ( R )-(+)-6-(1,4-dimethoxy-3-methyl-2-naphthyl)-6-(4-hydroxyphenyl)hexanoic acid ( R )- 2 , a key intermediate for a therapeutic drug for neurodegenerative diseases, has been developed. rac -Methyl 6-(1,4-dimethoxy-3-methyl-2-naphthyl)-6-(4-(propionyloxy)phenyl) hexanoate rac - 9b was synthesized from 2-methylnaphthoquinone in seven steps. An optically active ester ( R )- 9b was readily obtained from the corresponding racemic ester by lipase-catalyzed resolution, followed by sulfation or phosphorylation. Sulfation by a sulfur trioxide pyridine complex or phosphorylation by phosphoryl chloride enabled facile isolation of the optically active ester simply by extraction. Optically active acid ( R )- 2 was synthesized in excellent enantiomeric excess by hydrolysis of ( R )- 9b followed by recrystallization. The present synthesis of ( R )- 2 was accomplished in 10 steps without requiring chromatographic purification.

Large-scale synthesis of new cyclazines, 5-thia-1,8b-diazaacenaphthylene-3-carboxylic acid derivatives having the peripheral 12π-electron ring system

Abstract The 5-thia-1,8b-diazaacenaphthylenes ( 2 and its ester, 8 ) are new cyclazines, in which a paramagnetic ring is present in the peripheral 12π-electron ring system. Three convenient methods of preparing 8 have been developed. One involved thioglycolation of a new compound, 5-fluoroimidazo[1,2- a ]pyridine ( 6b ), followed by the Duff reaction gave 8 in 64% yield without chromatographic purification.

A Practical Synthesis of the Chronic Renal Disease Agent, 4,5-Dihydro-3H-1,4,8b-triazaacenaphthylen-3-one Derivatives, Using Regioselective Chlorination of Ethyl 5-methylimidazo[1,2-a]pyridine-3-carboxylate with N-Chlorosuccinimide

Abstract A convenient synthesis of the chronic renal disease agent, trifluoro-N-[4-(3-oxo-3,5-dihydro-4H-1,4,8b-triazaacenaphthylen-4-yl)butyl]methanesulfonamide (1a), for large scale has been developed via ethyl 5-(chloromethyl)imidazo[1,2-a]pyridine-3-carboxylate (3), which was given by the regioselective chlorination of ethyl 5-methylimidazo[1,2-a]pyridine-3-carboxylate (6) with N-chlorosuccinimide (NCS) using AcOEt as a solvent in 83% yield. The condensation of 3 and primary amines gave 4,5-dihydro-3H-1,4,8b-triazaacenaphthylen-3-one derivatives (1) in good yields. The present synthesis of 1a was accomplished in five steps from 2-amino-6-methylpyridine (4) without requiring a chromatographic method.

Convenient efficient synthesis of TAK-779, a nonpeptide CCR5 antagonist: development of preparation of various ammonium salts using trialkylphosphite and N-halogenosuccinimide

Abstract A convenient and efficient synthesis of TAK-779 (1a), a nonpeptide CCR5 antagonist, has been achieved. The new methylation of tertiary amine (2) using trimethyl phosphite and N-chlorosuccinimide, followed by the addition of HCl led to ammonium chloride (1a) in 89% isolated yield without requiring a chromatographic method. By this preparation, ammonium methanesulfonate (1e) could be obtained in 75% isolated yield.

Efficient syntheses of a novel 5-thia-1-azacycl[3.3.2]azine ring system and 3H-1,4-diazacycl[3.3.2]azine derivatives

Novel 5-thia-1-azacycl[3.3.2]azine derivatives 1 , 5-thia-1,8b-diazaacenaphthylenes, have successfully been prepared. An X-ray crystallographic analysis of 1c revealed that the 5-thia-1-azacycl[3.3.2]azine ring system adopts a planar structure as to the internal ring nitrogen atom. The 1 H NMR spectrum for unsubstituted ring system 1d implies contribution of a paramagnetic ring current in the peripheral 12π-electron ring system. Also, 3 H -1,4-diazacycl[3.3.2]azine derivatives, 4-benzyl-4,5-dihydro-3 H -1,4,8b-triazaacenaphthylen(e)-3-ones 2 and -3,5-diones 3 were synthesized with high efficiency via 3-(trichloroacetyl)imidazo[1,2- a ]pyridine derivatives as new useful synthetic intermediates.

Stable selenoxanthenium ylides : synthesis and new reductive cyclization of selenoxanthen-10-10(alkoxalyl alkoxycarbonyl)methanides and their related compounds

Abstract Stereoisomers of 9-substituted selenoxanthen-10-io (alkoxalyl alkoxycarbonyl)methanides were prepared from the corresponding selenoxides and activated acetylenes. In the reaction of 9-phenylselenoxanthene 10-oxide( 1c ) with methyl propiolate afforded an unexpected product, methyl 9-phenylselenoxanthen-9-ylpropiolate( 5 ) together with ylide( 2e ). The selenonium ylides underwent new reductive cyclization with sodium borohydride to afford new cyclic selenonium ylides.

CHEMISTRY OF CIS- AND TRANS-9-PHENYLSELENOXANTHENE-N-ARYLSULFONYLSELENILIMINES1

Abstract cis- and trans-9-Phenylselenoxanthene-N-(arylsulfonyl)selenilimines were synthesized and isolated. Their stereochemistry was ascertained from the NMR spectra. Cis isomers reacted with chloramine-T or -B by an SN 2 type substitution to form trans isomers, but the reverse reaction did not take place. When trans isomers were refluxed in toluene they underwent intermolecular 1,4 rearrangement to give 9-arylsulfonamido-9-phenylselenoxanthene. The cis isomers neither rearranged nor isomerized. On treatment with DABCO, both isomers rearranged intermolecularly to 9-(N-arylsulfonamido)selenoxanthenes at room temperature. Hydrolysis of both isomers yielded trans-9-phenylselenoxanthene 10-oxide. Reactions with p-methoxyphenylmagnesium bromide or methylmagnesium iodide afforded 9-(p-methoxyphenyl)-9-phenylselenoxanthene or 9-phenylselenoxanthene as a main product, respectively.

Stereoisomers of selenilimines: isolation and reactions of 9-phenylselenoxanthene-N-arylsulfonylselenilimines

Abstract The isolates cis- and trans-9phenylselenoxanthene-N-arylsulfonylselenilimines were not interconverted thermally. cis-Isomers were converted to trans-isomers by chloramine-T or -B in a fashion of SN2 type substitution. cis-Isomers did not rearrange but trans-isomers rearranged thermally to 9-arylsulfonamido-9-phenylselenoxanthenes, whereas both isomers underwent the base-catalyzed intermolecular rearrangement.