Ichizo Inoue

A synthesis of 2-aminonorbornene-2-carboxylic acid derivatives by diels-alder reaction using α,β-dehydroalaninates as a dienophile

Abstract The Diels-Alder reaction of N-acyl-α,β-dehydroalanine esters with cyclopentadiene afforded a mixture of the stereoisomers of acylaminonorbornene-2-carboxylic acid esters in good yields.

A synthesis of geminally functionalized heterocyclic aminocarboxylic acids by cycloaddition of ethyl N-acetyl-α,β-dehydroalaninate with 1,3-dipoles

Abstract 1,3-Dipolar cycloaddition of α,β-dehydroalaninate with dipoles proceeded with high regioselectivity to afford the title compounds in good yields.

A novel synthesis of 5-fluorouracil derivatives having oxacycloalkane moieties

Abstract 5-Fluorouracil derivatives having oxacycloalkane moieties were synthesized in good yields by the reaction of trimethylsilyloxyalkanal dialkyl acetals with 2,4-bis(trimethylsilyl)-5-fluorouracil in the presence of SnCl 4 .

Synthesis of uracil and thymine nucleosides of unsaturated 5-(aminoacyl)aminopentofuranoses

Abstract Improved syntheses of 1-(2,3-dideoxy-β- d - glycero -pent-2-enofuranosyl)-uracil ( 5a ) and -thymine ( 5b ) have been achieved via treatment of the corresponding 3′,5′-oxetane with sodium hydroxide in hexamethylphosphoric triamide. The 2′,3′-unsaturated nucleosides ( 5a and 5b ) were converted into 1-(5-amino-2,3,5-trideoxy-β- d - glycero -pent-2-enofuranosyl)-uracil ( 8a ) and -thymine ( 8b ), respectively. A new type of aminoacyl nucleoside, the 1-[5-(aminoacyl)amino-2,3,5-trideoxy-β- d - glycero -pent-2-enofuranosyl)-uracils and -thymines, has been obtained by condensation of 8a and 8b with the active esters of several amino acid derivatives followed by deprotection. These nucleosides were examined for in vivo antitumor activity against Sarcoma 180 (solid tumor). However, none of the compounds exhibited significant antitumor activity.

Studies on biologically active nucleosides and nucleotides. 7. Synthesis of some N4-acyl and N4-acylaminomethyl 2,2'-anhydronucleosides

The synthesis of N4-acyl-2,2’-anhydro1-( 3’,5’-di-O-acetyl-~-~-arabinofuranosyl)cytosine hydrotetrafluoroborates (2a-c) has been achieved via direct N4-acylation of the corresponding 2,2’-anhydronucleoside (la). The reaction of 2,2’-anhydro-1-(3’,5’-di-O-propionyl-~-~-arabinofuranosyl)cytosine hydrotetrafluoroborate (lb) with Nchloromethyl amides (6a,b) in the presence of boron trifluoride etherate gives the N4-(acylamino)methyl derivatives (8a,b). Mild acidic treatment of 8a and 8b gives the depropionylated derivatives (Ila,b) which, upon reaction with aqueous sodium bicarbonate, are converted into N4-[ (acylamino)methyl]-l-p-D-arabinofuranosylcytosines (13a,b).

Synthesis of new nucleosides containing a fused cyclopropane ring 1-{(1R,3R,5R)-2-oxabicyclo[3.1.0]hexan-3-yl}-thymine and -uracil

1-{(1R,3R,5R)-2-Oxabicyclo[3.1.0]hexan-3-yl}-thymine and -uracil have been obtained by the cathodic reduction of 3′,5′-dideoxy-3′,5′-di-iodothymidine and 2′,3′,5′-trideoxy-3′,5′-di-iodouridine, respectively.

The use of polyphosphoric ester and polyphosphoric acid in the synthesis of 1,4-dihydro-4-oxoquinolines

The synthesis of 1-alkyl-1,4-dihydro-4-oxoquinolines by the cyclization of derivatives of 2-(N-alkylanilino)acrylic acid in the presence of polyphosphoric acid or ester has been investigated. The results indicate that polyphosphoric ester is a more efficient reagent for the cyclization of 2-(N-alkylanilino)acrylic acid derivatives than polyphosphoric acid and also has advantages over the thermal cyclization.

Studies on the synthesis of Aspidosperma and related alkaloids. Part II. A synthetic approach to the C-21 oxygenated Aspidosperma alkaloids

An attempt was made to extend the total synthesis of (±)-aspidospermine (I) to the synthesis of (±)-limaspermine (IV). An eleven-step scheme starting from 5-phenoxypentan-2-one (XIV) gave (±)-21-phenoxyisopalosine (XXXIX), which was treated with hydrobromic acid to furnish the quaternary salt (XLII). The formation of this salt suggests that the stereochemistry of our products is not identical with that of the natural alkaloid.

SYNTHETIC STUDIES ON 2-PYRROLIDINONE DERIVATIVES. II. THE CONFIGURATION OF STEREOISOMERS OF 1-PHENYL-3-AMINO-5-METHYL-2-PYRROLIDINONE.

The reductions of 1-phenyl-3-hydroxyimino-5-methyl-2-pyrrolidinone, using i) Platinum dioxide in glacial acetic acid, ii) Raney nickel in Ethanol, and iii) Aluminum mercury in moist tetrahydrofuran, were carried out to furnish two isomeric amines, designated as IIa and 1-phenyl-3-amino-5-methyl-2-pyrrolidinone (IIb). Quantitative ratios of these amines formed as regard to the reduction methods allowed us to assign cis-configuration to IIb and trans-configuration to IIa. From the studies of ultraviolet and nuclear magnetic resonance spectra of the 3-hydroxy-compounds, 1-phenyl-3-hydroxy-5-methyl-2-pyrrolidinone (IIIa) and 1-phenyl-3-hydroxy-5-methyl-2-pyrrolidinone (IIIb), prepared from IIa and IIb respectively, the occurrence of Walden-inversion in the diazotization reaction was concluded. At the same time cis-configuration of IIb and IIIa was also predicted, which was supported by leading IIIa to cis-1-tosyl-2-methyl-4-methoxypyrrolidine (X) synthesized from dl-allo-hydroxyproline.