Alkaline hydrolysis of 2-(trifluoromethyl)imidazo[4,5-f] and -[4,5-h]quinolines

2-(Trifluoromethyl)imidazo[4,5-$\text{f}$] and -[4,5-$\text{h}$]quinoline have been prepared from 5(6),acetamido-2-(trifluoromethyl)benzimidazole and 7,8-diaminoquinoline respectively. These (trifluoromethyl)- quinolines like 2-(trifluoromethyl)imidazoles but unlike 2-(trifluoromethyl) benzimidazoles, undergo hydrolysis in dilute sodium hydroxide to give ultimately the corresponding imidazo[4,5-$\text{f}$] and -[4,5-$\text{h}$]- quinoline, respectively.     

BH3 THF reduction of 3-methylisoxazolo [4,5-c]pyridines

3-Methylisoxazolo[4,5-c]pyridine $\text{1}$ on reduction with BH₃:THF gave, via the isolable complex $\text{4}$, the tetrahydroisoxazolopyridine $\text{5}$. The presence of two chlorine atoms at the 4 and 6 positions directed borane attact to the isoxazole ring, yielding the aminoethylpyridine $\text{8}$. Both types of reduction were obtained with 6-chloroisoxazolo[4,5-c]pyridine $\text{7}$.     

A biogenetically significant cyclization of humulene-4,5-epoxide

Rearrangement of humulene-4,5-epoxide with boron trifluoride etherate leads to the formation of two tricyclic alcohols the structures of which are closely related to that of africanol; the $\text{X}$-ray structure of the $\text{p}$-bromobenzoate of one of the alcohols is reported.     

1,3-dichloromethine cyanine condensation with 1,3-dimethyl-4,5-diamino uracil producing a new spiro-heterocycle

Trimethinium salts $\text{1}$ cyclize with 4,5-diaminouracil to give the new spiroheterocyclic systems $\text{6}$     

Total synthesis of (±)-xanthocidin and (±)-desdihydroxy-4,5-dihydroxanthocidin

The first total synthesis of both (±)-xanthocidin ($\text{1}$), a novel α-methylene cyolopentanoid antibiotic, and (±)-desdihydroxy-4,5-dihydpoxanthocidin ($\text{2}$), the likely penultimate biosynthetic precursor is reported.     

A facile three-step synthesis of a racemic 4,5-diamino-dideoxy-α-D, β-L-lyxopyranose.

Diels-Alder cycloaddition of nitrosobenzene to 1-methoxycarbonyl-1,2-dihydropyridine led in high yield to the endocyclic hydroxylamine adduct $\text{5}$, which was successively oxydized with potassium permanganate and hydrogenolyzed to give the new aminosugar 4,5-dideoxy-5-methoxycarbonylamino-4-phenylamino-α-$\text{D}$, β-$\text{L}$ lyxopyranose $\text{7}$.     

Stereoselective conversion of allylic alcohols to n-acyl-trans-4,5-dialkyloxazolidines.

The stereoselective synthesis of N-acyl-$\text{trans}$-4,5-dialkyloxazolidines (precursors to $\text{threo}$-β-amino alcohols) through a procedure involving amidomethylation of a 2° allylic alcohol followed by mercuric-ion inititated cyclofunctionalization is reported.     

Acid - catalyzed rearrangement of butyl 2-0-acetyl-4,5-anhydro-3,6-dideoxy-hexaldonate. Synthesis of racemic epiallomuscarine and epimuscarine

Butyl 2-0-acetyl-4,5-anhydro-3,6-dideoxy-DL-xylo-hexaldonate ($\text{4}$) in the presence of SnCl₄ underwent an intramolecular rearrangement to give 2,5-anhydro ester $\text{7}$. On the other hand the lyxo epimeric epoxide $\text{5}$ under the same conditions afforded esters $\text{7}$ and $\text{8}$. Ester $\text{7}$ was transformed into racemic epiallomuscarine ($\text{12}$), whereas the isomer $\text{8}$ into racemic epimuscarine ($\text{13}$).     

Chemistry of ketene acetals II. A simple route to 2,2-dialkoxytetrahydrofurans, γ-butyrolactones, 2-(5H)-furanones and 2-alkoxy-4,5-dihydrofurans

2,2-Dialkoxytetrahydrofurans $\text{3}$ (a,b) have been synthesized from epoxides $\text{1}$ and ketene acetals $\text{2}$ using ZnCl₂ as a catalyst. By simple reactions compounds $\text{3}$ were converted into γ-butyrolactones $\text{5}$, 2-(5H)-furanones $\text{7}$ and 2-alkoxy-4,5-dihydrofurans $\text{8}$.     

Stereochemical studies—76 saturated heterocycles—63 : synthesis of cis- and trans-n-methyl- and n-benzyl-4.5- and 5,6-tetramethylenetetrahydro-1,3-oxazines; an x-ray study of n-benzyl-cis-4,5-tetramethylenetetrahydro-1,-3-oxazinium- picrate

- The corresponding $\text{cis}$- and $\text{trans-N}$-methyl- and $\text{N}$-benzyl-5,6- and 4,5-tetramethylenetetrahydro-l,3-oxazines $\text{(5a,b-8a,b)}$were synthesized from $\text{cis}$- and $\text{trans-N}$-methyl and$\text{N}$-benzyl-2- aminomethyl-1-cyclohexanols $\text{1a,b,2a,b}$, from $\text{cis}$- and $\text{trans-N}$-methyl- and $\text{N}$benzyl -2-hydroxymethyl-1-cyclohexylamines$\text{(3a,b,4a,b)}$ by reaction with formaldehyde. The aminoalcohols $\text{1a,2a,3a,b}$and $\text{4a,b}$ were prepared in considerably higher yields than in earlier procedures. NMR spectroscopy showed that the $\text{cis}$ isomers of the synthesized oxazines were conformationally homogeneous in solution, and their preferred conformation (inside or outside) depended on the steric requirement of the groups attached to the anellation points, whereas a bulky C-2 substituent had no influence on the predominant conformation. The structure of $\text{N}$-benzyl-$\text{cis}$-4,5-tetramethylenetetrahydro-1,3-oxaziniumpicrate $\text{(7b)}$. determined by X-ray diffraction analysis, was in agreement with the predominant N-outside conformation of the corresponding base, established by means of NMR spectroscopy.     

A convenient synthesis of 1,3-dimethyl(5h,7h)imidazo(4,5-dpyrimidine-2,4,6-trithione and its unusual character

1,3-Diemthyl(5H,7H)imidazo(4,5-$\text{d}$pyrimidine-2,4,6-trithione ($\text{1}$) was synthesized by the reaction of carbon disulfide with 1,3-dimethyl-4-cyano-5-aminoimidazolidine-2-thione ($\text{3}$) which was produced by reacting trimethylsilyl cyanide with methyl isothiocyanate followed by methanolysis. An unusual reversible formation of the dimethylamine salt of $\text{1}$ is also described.     

Iron(II) complexes of pyrazol-4,5-dione-5-oximes

The complexes Fe(po)₂·H₂O, Fe(Ppo)₂·H₂O and Fe(PPo)₂·2py, where poH = 3 - methyl - 4 - oxime - 1H - pyrazole - 4,5 - dione and PpoH = 3 - methyl - 4 - oxime - 1 - phenyl - 1$\text{H}$ - pyrazole - 4,5 - dione, have been prepared. The magnetic susceptibilities and Mössbauer spectra of the complexes have been investigated.     

A Wittig reaction on mucochloric and mucobromic acids. Preparation of ethyl (2E, 4Z -4,5-dihalo-2,4-pentadienoates and alkyl 2E -5-bromo-2-penten-4-ynoates

Reaction of mucochloric and mucobromic acid with (ethoxycarbonylmethylene) triphenyl-phosphorane affords the ethyl ester of (2$\text{E}$, 4$\text{Z}$ -4,5-dichloro- and (2$\text{E}$, 4$\text{Z}$) -4, 5-dibromo-2,4-pentadienoic acid respectively; in the latter case ethyl (2$\text{E}$ -5-bromo-2-penten-4-ynoate is formed concomittantly.     

Synthese de la phenyl-2-dimethyl-4,5-phosphorine a partir du benzyl-1-dimethyl-3,4-phosphole

1-Benzyl-3,4-dimethylphosphate

-$\text{1}$ is converted into 2-phenyl-4,5-dimethyl-λ₃-phosphorin

-$\text{2}$ through 1,2-dihydro-λ₅-phosphorines

$\text{3}$ and

$\text{s}$.     

Cyclic enediol phosphoranes obtained from the reaction of trimethyl phosphite with biacetyl and hexafluorobiacetyl give strikingly different acylation products

Cyclic enediol phosphoranes (2,2,2-trimethoxy-2,2-dihydro-l,3, 2-dioxaphospholenes), prepared from α-diketones, RCOCOR, and trimethyl phosphite (TMP), give strikingly different acylation products depending on the electronic properties of the groups, R, that occupy the 4,5-positions in the dioxaphospholene ring with pentacovalent phosphorus. Reaction of acetyl chloride or bromide with the hexafluorobiacetyl-TMP phosphorane gives exclusively the product of $\text{endo}$cyclic O-acylation, dimethyl(2-acetoxy-$\text{cis}$-1,2, -$\text{bis}$trifluoromethylvinyl) phosphate. Acylation of the biacetyl-TMP phosphorane gives mixtures of the product of $\text{exo}$cyclic O-acylation (a cyclic enediol phosphate) and the product of C-acylation (an α-hydroxy-β-diketone phosphate), the proportions depending on the structure of the acyl halide and the solvent. The parent 1,3,2-dioxaphospholene, i.e., the glyoxal-TMP phosphorane where R = H, gives exclusively the product of $\text{endo}$cyclic O-acylation with both acyl halides in all solvents.     

Base-catalyzed oxygenation of 2,6-di-t-butylanilines: X-ray analysis of 2,4,6-tri-t-butyl-4,5-epoxy-6-hydroxy-2-cyclohexen-1-imine

Oxygenation of 2,4,6-tri-t-butylaniline (1a) catalyzed by t-BuOK in hexamethylphosphoric triamide (HMPA) at 75° leads to the incorporation of molecular oxygen into the aromatic ring giving rise to 2,4,6-tri-t-butyl-4,5-epoxy-6-hydroxy-2-cyclohcxen (12a). A similar result is obtained in the oxygenation of 2,6-di-t-butyl-4-phenylaniline (11b). The oxygenation of 11a in toluene containing n-BuLi gave exclusively 2,4,6-tri-t-butyl-nitrosobenzeoe. The oxygénation of 2,6-di-t-butyl-4-methoxyaniline (1d) in tetrahydrofuran with n-BuLi gave dimeric products in fairiy good yields. The structure of 12a has been confirmed by X-ray analysis. The crystals are monoclinic ($\text{P2}{}_1\text{a}$) with a = 9.99, b = 23.16, c = 8.70 Å, β = 116.19°; Z = 4. The structure was determined by direct methods and refined to R = 0.089.     

A synthetic approach to (+)-aldosterone and its relatives (2)- a stereoselective synthesis of (+)-trans-4,5-(4-methoxybenzo)- 1β , 7aβ - ( 2α-methoxymethyl- 5 -oxofuro) hydrindane

A stereoselectivity in an intramolecular cycloaddition of the olefinic $\text{o}$-quinodimethanes 13 and 23 generated $\text{in}$$\text{situ}$ from the thermolysis of optically active 4β-[2-(4-methoxybenzocyclobutenyl)ethyl] -5α-methoxymethyl-3-phenyl-thio-methylenefuran-2-ones 12 and 22, respectively, is studied and a stereoselective synthesis of (+)-$\text{trans}$-4,5-( 4-methoxybenzo) -1β,7aβ-(2α-methoxymethyl-5-oxofuro)hydrindane 1 is also described.     

Transition metal(ii) schiff's base complexes catalyzed oxidation of trans-2-(1-propenyl)-4,5-methylenedioxyphenol to carpanone by molecular oxygen

Carpanone was synthesized in an excellent yield by the oxidation of $\text{trans}$-2- (1-propenyl) -4,5-methylenedioxyphenol with molecular oxygen in the presence of transition metal complexes such as Co(II)salen, Co(II)salpr, Fe(II)salen, and Mn(II)salen.