Biologically active quassinoids : synthetic methodology for the conversion of chaparrin into glaucarubolone esters and quassinoid analogs

Biologically inactive but easily available chaparrin $\text{2a}$ has been converted into potent antileukemic C-15 esters of glaucarubolone $\text{2b}$ and quassinoid analogs in which the C-15 ester side chain has been replaced by an alkyl or alkenyl group.The synthetic methodology developed has been applied to the preparation of C-15 ester derivatives $\text{15}$, $\text{16}$, $\text{17}$ and quassinoid analogs $\text{12}$, $\text{13}$ and $\text{14}$.     

Synthetic studies toward phenoxan analogs

We developed two reactions needed for a total synthesis of phenoxan, a naturally occurring compound with anti-HIV activity. In this Note, we further examined these two issues: metallation of a 2-methyl-oxazole and formation of a pyran-4-one. We employed these methods for the preparation of a phenoxan analog.     

Synthetic studies leading to DE-ring analogs of camptothecin

A synthetic scheme leading to an isomeric DE ring ( 14 ) of the anti-tumor alkaloid, camptothecin, has been achieved. However, the method failed to give the correct pyridone lactone ( 2 ) found in this alkaloid.     

Synthetic and modified isoflavonoids XIV. Mannich bases and their salts in a series of synthetic isoflavone analogs

Mannich bases and their hydrochlorides have been obtained from 1,3-benzodioxolane, 1,4-benzodioxane, and 1,5-benzodioxepane analogs of pseudobaptigenin. The PMR spectra of the compounds obtained are given and are discussed.Translated from Khimiya Prirodnykh Soedinenii, No. 5, pp. 625–629, September–October, 1994.     

Synthetic and modified isoflavonoids XIV. Mannich bases and their salts in a series of synthetic isoflavone analogs

New 2,6-dialkyl-substituted isoflavone analogues of the natural isoflavone pseudobaptigenin have been synthesized. Their structures have been confirmed by IR and PMR spectroscopies.Taras Shevchenko University, KIEN. Karakalpak Division. Academy of Sciences of the Republic of Uzbekistan. Translated from Khimiya Prirodnykh Soedinenii, No. 5, pp. 674–677, September–October, 1993.     

Synthetic studies toward the development of novel minoxidil analogs and conjugates with polyamines

Syntheses of novel polyamine-modified minoxidil analogs (PMMs) and minoxidil-polyamine conjugates (MPCs) are described in an effort to improve the biological activity and selectivity of minoxidil and its poor solubility in water.     

Further Synthetic Studies on the Conversion of Alcohols into Phenylthio Ethers

The conversion of sterically encumbered alcohols into their corresponding phenylthio ethers employing phenyl disulfide and tri-n-butylphosphine was investigated.     

Amino acids and peptides. XIII. Synthetic studies on N-terminal tripeptide amide analogs of fibrin alpha-chain

N-Terminal tripeptide analogs of fibrin alpha-chain were synthesized and their inhibitory effect on fibrinogen/thrombin clotting was examined. A new water-soluble active ester, 3-pyridinium ester, was used for the synthesis. Among the synthetic peptides, H-Gly-Pro-Arg-hexamethyleneimine exhibited the highest inhibitory effect on fibrinogen-thrombin clotting.     

Synthetic analogs of natural flavolignans. VI. Synthesis of analogs of silybin and dehydrosilybin

Analogs of silybin and dehydrosilybin have been obtained from 1,4-benzodioxane derivatives of chalcones, and their structures have been shown by their PMR and IR spectra.     

Synthetic studies in the tetranorditerpene lactone series. I. The total synthesis of dihydro-8-epi-acrostalidic acid

The total synthesis of dihydro-8-epi-acrostalidic acid ($\text{8b}$) and other related tetranorditerpene lactones are described.     

Synthetic analogs of natural flavolignans. IV. Synthesis of benzodioxocane analogs of silandrin and hydnocarpin

1,6-Benzodioxocane analogs of chalcones have been synthesized. From them have been obtained benzodioxocane analogs of silandrin and hydnocarpin. The PMR spectra of the substances synthesized are given and are discussed.Taras Shevchenko Kiev University, Ukraine. KIEN, Karakalpak Division, Academy of Sciences of the Republic of Uzbekistan, Nukus. Translated from Khimiya Prirodnykh Soedinenii, No. 4, pp. 490–493, July–August, 1994.     

Synthetic analogs of natural flavolignans. IV. Synthesis of benzodioxocane analogs of silandrin and hydnocarpin

1,6-Benzodioxocane analogs of chalcones have been synthesized. From them have been obtained benzodioxocane analogs of silandrin and hydnocarpin. The PMR spectra of the substances synthesized are given and are discussed. Taras Shevchenko Kiev University, Ukraine. KIEN, Karakalpak Division, Academy of Sciences of the Republic of Uzbekistan, Nukus. Translated from Khimiya Prirodnykh Soedinenii, No. 4, pp. 490–493, July–August, 1994.     

Synthetic and modififed isoflavones. VIII. New analogs of derrusnin

Derivatives of derrusnin and also its benzodioxane and benzodioxepane analogs have been synthesized. The structures of the compounds obtained have been confirmed by spectral studies.     

Synthetic analogs of histones and protamines

Conclusions We prepared the polytri- and polytetrapeptides (mol.wt. 2000–9000) containing the sequence: -Ala-Ala-Lys(Cbo)-;-Lys(Cbo)-Lys(Cbo)-Ala-; -Lys(Cbo)-Lys(Cbo)-Gly-; -Ala-Ala-Ala-Lys(Cbo)-; Lys(Cbo)-Lys(Cbo)-Lys(Cbo)-Ala-; -Orn(Cbo)-Orn(Cbo)-Ala-Ala-;-Orn(Cbo)-Orn(Cbo)-Gly-Gly-; -Lys (Cbo)-Lys-(Cbo)-Ala-Ala-;-Lys(Cbo)-Lys (Cbo)-GIy-Gly-.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 2, pp. 435–439, February, 1973.