Phenothiazine syntheses. XVIII. 2-Aminophenothiazine derivatives

2-(-chloroacetylamido)-2-(-chloropropionylamido)-2-(benzylideneamino)- and 2-(o-hydroxybenzyllideneamino)phenothiazines are synthesized and reduced by lithium aluminum hydride to 2-ethylamino-, 2-propylamino-, 2-benzylamino-, and 2-(o-hydroxybenzylamino)phenothiazine. Reduction of the methyl and ethyl esters of phenothiazinecarbamic-2 acid by lithium aluminum hydride gives 2-methylaminophenothiazine.For Part XVII see [1].     

Phenothiazine syntheses

A new method of preparing 3-aminophenothiazine by hydrogenating 3-nitro-5-hydroxyphenothiazine in acetic acid or ethanol solution is developed. A number of derivatives of that amine are synthesized.     

β-Ketolactone synthons. Short efficient syntheses of jasmonoids.

The cyclopentanoid β-ketolactone $\text{2}$, serving as the equivalent of a specific enolate of a 3-alkyl cyclopentanone, has been converted to several jasmonoid substances.     

Efficient total syntheses of polygodial and drimenin.

A short and stereoselective total synthesis of (±) polygodial and drimenin is presented. The efficiency of the synthesis is due to the easy access to intermediate diol $\text{4}$ and its successful direct oxidation into polygodial.     

New heterocyclic syntheses from hydrazidoyl halides. Convenient syntheses of fused pyrimidines,pyridazines, and quinazolines

Aminocyanopyrazole derivatives and pyrazolo[2,3-a]quinazolones were obtained in good yields from hydrazidoyl halides and malononitrile. Pyrazolo[3,4-d]pyridazine and pyridazo[4′,5′: 1,2]pyrazolo[1,5-a]quinazoline derivatives were synthesized in quantitative yields by reaction of hydrazine hydrate with 2 and 16 , respectively. A novel ring system, a 3-substituted tetrahydro derivative of 7-oxo-6H,8H-pyridazo[3′,4′,5′-c'd']-pyrazolo[3,4-d]pyrimidine was prepared by reaction of 6 with dimethyl carbonate. Pyrazolo[3,4-d]pyrimidine-4,6-dithiones were obtained in good yields by reaction of 2 with carbon disulfide. The structures of the products were assigned and confirmed on the basis of their elemental analyses, spectral data, and alternate synthesis wherever possible. The structures of the parent fused heterocyclic systems discussed in this work are summarized in Scheme 1 .     

Reissert compound chemistry. XXVI. The syntheses of bis-benzylisoquinolines

The condensation of the anion of isoquinoline Reissert compounds with diaryl ethers is reported. These condensation products are converted into analogues of bis-benzylisoquinoline alkaloids.     

New polymer syntheses XII. Polyketones based on diarylidenecycloalkanones

Two new series of polyketones containing diarylidene links was synthesized by the Friedel-Crafts polymerization of diarylidenecyclopentanone or diarylidenecyclohexanone with aromatic diacid chlorides, azodibenzoyl chlorides, or aliphatic diacid chlorides. The resulting polymers had inherent viscosities in the range 0.76-1.18 dl/g and showed poor solubilities to common organic solvents excepts strong acids. The thermal stabilities of these polymers were evaluated and correlated to their structural units by thermogravimetric analysis (TGA), DTG and DSC measurements. The TGA data revealed 10% weight losses at 190-300 °C. Moreover, the crystallinity of some polymers were tested by X-ray analyses and the UV-visible spectra showed characteristic absorption bands in the range 240-350 nm.     

Concise asymmetric syntheses of radicicol and monocillin I.

Radicicol (1) exhibits potent anticancer properties in vitro, which are likely to be mediated through its high affinity (20 nM) for the molecular chaperone Hsp90. Recently, we reported the results of a synthetic program targeting radicicol (1) and monocillin I (2), highlighted by the application of ring-closing metathesis to macrolide formation. These efforts resulted in a highly convergent synthesis of radicicol dimethyl ether but failed in the removal of the two aryl methyl ethers. Simple exchange of these methyl ethers with more labile functionalities disabled a key esterification in the initial route. Through extended experimentation, a successful route to both natural products was secured, along with some intriguing results that emphasize the implications of this design on a broad range of fused benzoaliphatic targets, including analogues of these natural products.     

Stereocontrolled syntheses of carbocyclic C-nucleosides and related compounds.

Carbocyclic 9-deazapurine nucleosides (1-4), a spiranic pyrimidone carbocyclic compound (5), and an unusual carbocyclic isonucleoside (6) were prepared as enantiomerically pure compounds via the key intermediates 10 and 21 from 1,4-gamma-ribonolactone. The key intermediate 10 was prepared by stereoselective reduction with Bu3SnH and then converted to carbocyclic C-ribonucleosides 1, 3, and 4. 2',3'-Didehydro-2',3'-dideoxycarbocyclic 9-deazainosine (2) was prepared from a 2',3'-dimesylate 17 by treatment with Li2Te followed by an acidic deprotection. The key bicyclic intermediate 21 was prepared from a diol 20 by an intramolecular cyclization using CHI3-Ph3P-imidazole and converted to the spiranic compound 5 and an olefinic nucleoside 6 by the construction of the heterocyclic moiety followed by deprotection.     

Tethered dithiacyclopropenones. syntheses and structural properties of tetrathiacyclopropenonophanes

The reaction of the cyclic tetrathiadiynes 4(m.n) (where m and n indicate the number of methylene groups between the dithiaacetylene units) with sodium trichloroacetate and subsequent hydrolysis of the gem-dichlorocyclopropenes afforded the mono- and biscyclopropenone derivatives 5(m.n) and 6(m.n) in moderate yields. Investigation of the X-ray crystal structures revealed small torsion angles between the CH(2)-S bond and the C-C double bond, indicating conjugation between the sulfur 3p lone pair and the cyclopropenone ring. The maintenance of the conjugation determines the secondary structure of both (5, 6) ring systems.     

Studies on the syntheses of azole derivatives. Part VIII. Photolysis of N-aryl-N-benzylearbamoyl azides [studies on the syntheses of heterocyclic compounds. Part CDXV

Photolysis of N-benzyl-N-phenylearbamoylazide (IVc) afforded 1-benzy 1-2-benzimidazolinone (Ic), 2-benzimidazolinone (IIe), 4-benzy 1-2-benzimidazolinone (IIe), and 5-benzy1-2-benzimidazo-linone (IIf)- The same reaction of N-benzyl-N-(4-chlorophenyl) carbamoyl azide (IVd) gave 3-benzyl-1-(phenylhydrazocarbonyl)-2-benzimidazolinone (VIb) besides the above four products. In the case of N-benzyl-4-(4-butoxyphenyl)carbamoyl azide (IVe), 1-benzy1-5-butoxy-2-benz-imidazolinone (1e), 5-butoxy-2-benzimidazolinone (IId), 5-benzy1-2-benzimidazolinone (IIf), and 4-benzy1-6-butoxy-2-benzimidazolinone (IIg).