Isoquinoline derivatives

6,7-Dimethoxy-1,2,3,4-tetrahydroisoquinoline-4-spirocyclopentane was obtained by condensation of 3,4-dimethoxyphenyl-1-(aminomethyl)cyclopentane with formalin. The corresponding amides, which were reduced to tertiary amines, were synthesized by reaction of the latter with the acid chlorides of substituted benzoic and phenylacetic acids. Substituted dibenzo[a,-g]quinolizines, isoindolo[1,2-a]isoquinolines, and 1-(3,4-dimethoxyphenyl)-1-[(6,7-dimethoxy-1, 2,3,4-tetrahydro-2-isoquinolinyl)methyl]cyclopentane were synthesized, respectively, by condensation of 1-aryl (or aralkyl)-6,7-dimethoxy-1,2,3,4-tetrahydroisoquinoline-4-spirocyclopentanes and their open analog -1-(3,4-dimethoxyphenyl)-1-(3,4-dimethoxyphenylethylaminomethyl)cyclopentane — with formalin.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 679–682, May, 1973.     

The synthesis of 1-haloalkyl-1,3,4,5-tetrahydro-2-benzoxepins

Short, efficient routes to several 7,8-dimethoxy-1-haloalkyl-1,3,4,5-tetrahydro-2-benzoxepins were developed. These benzoxepins were prepared by the Lewis acid catalyzed condensation of the acetals of chloropropionaldehyde or bromoacetaldehyde with 3-(3,4-dimethoxyphenyl)-1-propanol. This condensation was facilitated by methyl substitution on the propanol. In an alternate route, ethyl 3-(3,4-dimethoxyphenyl)propanoate was acylated with 3-chloropropionyl chloride. The adduct was reduced with lithium aluminum hydride. The resultant 3-[2-(3-chloro-1-hydroxypropyl)-4,5-dimethoxyphenyl]propanol was dehydrated to the corresponding tetrahydrobenzoxepin. By these two general routes, 7,8-dimethoxy-1,3,4,5-tetrahydro-2-benzoxepins were produced which were substituted by hydrogen or methyl at benzoxepin C-4 and chloroethyl or bromomethyl at benzoxepin C-1.     

Formation and Ring Contraction of Benzo[f][1,2]Thiazepine-1,1-Dioxides from and to Benzo[e][1,2]Thiazine-1,1-Dioxides

Alkoxide-promoted ring expansion of the novel ethyl 2-(6,7-dimethoxy-3-oxo-3,4-dihydrobenzo[e][1,2]thiazine-1,1-dioxide-2-yl)acetate 3a and analogous 4,4-diethyl derivative 3b and cyclization of methyl 2-[2-(phenylaminocarbonylmethyl sulfamoyl)-4,5-dimethoxyphenyl] acetate 9 to the corresponding new 3-carboxylates and 3-carboxanilide of 7,8-dimethoxy-4-hydroxy-2,5-dihydrobenzo[f][1,2]thiazepine-1,1-dioxide (5a,b and 10 respectively) is described. Compound 5a was deacylated upon treatment with sodium hydroxide followed by hydrochloric acid to give 7,8-dimethoxy-2,3-dihydrobenzo[f][1,2]thiazepine-1,1-dioxide-4 (5H)-one 8 and its N-ethyl derivative transferred to 6,7-dimethoxy-2-ethyl-3-oxo-3,4-dihydrobenzo[e][1,2]thiazine-1,1-dioxide 7 by the reaction with ethyl methyl ketone in the presence of pyrrolidine.     

The Use of 4-(Bromomethylene)-5,5-dimethyl-1,3-dioxolan-2-one as “Masked” α-Bromo-α'-Hydroxy Ketone in the Synthesis of Heterocyclic Systems

4-(Bromomethylene)-5,5-dimethyl-1,3-dioxolan-2-one was obtained on the basis of the readily obtainable 4-methylene-5,5-dimethyl-1,3-dioxolan-2-one. It forms 2-imidazo[1,2-a]pyridin-2-yl-2-propanol with 2-aminopyridine, 11a-hydroxy-1,1-dimethyl-3-oxo-1,5,11,11a-tetrahydro[1,3]oxazolo[3,4-a]pyrido[1,2-d]-10-pyrazinium bromide with 2-(aminomethyl)pyridine, and the corresponding derivative of 4-hydroxyoxazolidin-2-one with 2-(3,4-dimethoxyphenyl)ethylamine. The last product was converted by intramolecular amidoalkylation without isolation into 10b-(bromomethyl)-8,9-dimethoxy-1,1-dimethyl-1,5,6,10b-tetrahydro[1,3]oxazolo[3,4-a]isoquinolin-3-one.     

Aromatic compounds from the liverwort Conocephalum japonicum

Two undescribed dimeric ArC2 derivatives, cis- and trans-1,2-bis(3,4-dimethoxyphenyl)cyclobutane (1 and 2), one new monoterpenes esters, 2alpha,5beta-dihydroxybornane-2-cis-cinnamate (3), along with eight known compounds, 2alpha,5beta-dihydroxybornane-2-trans-cinnamate (4), perrottetin E (5), isoriccardin C (6), marchantin A (7), marchantin E (8), marchantin C (9), and isomarchantin C (10) were isolated from the liverwort Conocephalum japonicum. All the structures were established by extensive spectroscopic analysis. The isolated compounds 3-10 were evaluated for their cytotoxicity against the human KB cell line with IC50 values ranging from 16.5 to 50.2 microM.     

Bischler-Napieralski Reaction of 2-(3,4-Dimethoxy-2-nitrophenyl)-N-[2-(3,4-dimethoxyphenyl)ethyl]-N-[(S)-1-phenylethyl] acetamide Accompanied by Elimination of Chiral Auxiliary

Chiral 1-benzyltetrahydroisoquinoline alkaloids can be asymmetrically synthesized via Bischler-Napieralski (B-N) cyclization followed by stereoselective NaBH4 reduction (Polniaszek抯 method) of the N- (2-phenylethyl)-2-phenylacetamides bearing chiral auxiliary such as (S)-1-phenylethyl group on the nitrogen atom1-4. Recently Y. Ohishi and co-workers found an unusual B-N reaction on the carbon at 2-position of the A ring, which bears a bromine atom5, 6. They indicated that the steric ef…     

A synthesis of 3-phenyl-1,2,3,4-tetrahydroisoquinoline and 2-phenyl-1,2,4,5-tetrahydro-3H-3-benzazepine via Pummerer-type cyclization: enhancing effect of boron trifluoride diethyl etherate on the cyclization

A synthesis of 6,7-dimethoxy-3-phenyl-1,2,3,4-tetrahydroisoquinoline (14a) and 7,8-dimethoxy-2-phenyl-1,2,4,5-tetrahydro-3H-3-benzazepine (14b) was achieved via the cyclization of N-(3,4-dimethoxyphenyl)methyl-1-phenyl-2-(phenylsulfinyl)ethylformamide (6a) and N-2-(3,4-dimethoxyphenyl)ethyl-1-phenyl-2-(phenylsulfinyl)-ethylformamide (6b) using the Pummerer reaction as a key step, respectively. The Pummerer reaction of 6a,b under usual conditions using trifluoroacetic anhydride yielded the vinyl sulfides (8a, b), non-cyclized products, as a major product. The cyclization proceeded when boron trifluoride diethyl etherate was used as an additive reagent, thus giving rise to the corresponding cyclized products (7a) and (7b) in moderate yields. We propose that the enhancing effect of the Lewis acid on the cyclization may be attributable to the involvement of a dicationic intermediate, sulfonium-carbenium dication (23).     

Diastereoselective synthesis of 3,4-dimethoxy-7-morphinanone: a potential route to morphine

[reaction: see text] Diastereoselective synthesis of racemic 3,4-dimethoxy-7-morphinanone from racemic 2-(2,3-dimethoxyphenyl)cyclohexen-1-ol has been achieved. The relative structure has been determined by transformation of the product into the known 3, 4-dimethoxy-6-morphinanone. Resolution of the starting cyclohexenol has also been accomplished for use in a future enantiocontrolled synthesis of morphine.     

Two new compounds from Dendrobium candidum

Two new compounds were isolated from the stems of Dendrobium candidum: (R)-3,4-dihydroxy-5,4',alpha-trimethoxybibenzyl (1), named dendrocandin A; and 4-[2-[(2S,3S)-3-(4-hydroxy-3,5-dimethoxyphenyl)-2-hydroxymethyl-8-methoxy-2,3-dihydrobenzo[1,4]dioxin-6-yl]ethyl]-1-methoxyl benzene (2), dendrocandin B. Five previously known bibenzyls were also identified: 4,4'-dihydroxy-3,5-dimethoxybibenzyl (3), 3,4-dihydroxy-5,4'-dimethoxybibenzyl (4), 3-O-methylgigantol (5), dendrophenol (6), and gigantol (7).     

Alpha-glucosidase inhibitory constituents from Cuscuta reflexa

Two new compounds, 7'-(3',4'-dihydroxyphenyl)-N-[(4-methoxyphenyl)ethyl]propenamide (4), and 7'-(4'-hydroxy,3'-methoxyphenyl)-N-[(4-butylphenyl)ethyl]propenamide (5) have been isolated from Cuscuta reflexa along with five known compounds, 6,7-dimethoxy-2H-1-benzopyran-2-one (1), 3-(3,4-dihydroxyphenyl)-2-propen-1-ethanoate (2), 6,7,8-trimethoxy-2H-1-benzopyran-2-one (3), 3-(4-O-beta-D-glucopyranoside-3,5-dimethoxyphenyl)-2-propen-1-ol (6), 2-(3-hydroxy-4-methoxyphenyl)-3,5-dihydroxy-7-O-beta-D-glucopyranoside-4H-1-benzopyrane-4-one (7), reported for the first time from this species. Structures of these compounds were determined by spectral analysis. These compounds showed strong inhibitory activity against alpha-glucosidase.     

The synthesis of angularly fused polyaromatic compounds by using a light-assisted, base-mediated cyclization reaction

The synthesis of substituted polyaromatic compounds that contain at least four benzene rings fused together in an angular fashion is described. Suzuki coupling of 1-bromo-3,4-dihydronaphthalene-2-carbaldehyde with a number of aromatic boronic acids affords products such as 1-(1,4-dimethoxy-3-methyl-2-naphthyl)-3,4-dihydronaphthalene-2-carbaldehyde. Exposure of these dihydronaphthalenes to potassium tert-butoxide and DMF at 80 degrees C yields polyaromatic compounds such as 9,14-dimethoxynaphtho[1,2-a]anthracene.     

The first example ot the benzo[b]pyrimido[4,5-f]azocine king system

Base catalyzed cyclization of ethyl 4-[2-(2-amino-4,5-dimethoxyphenyl)ethyl]-2-phenylpyrimidine-5-carboxylate, derived from ethyl 4-methyl-2-phenyl-5-pyrimidinecarboxylate and 3,4-dimethoxy-6-nitrobenz-aldehyde, gave 5,6-dihydro-8,9-dimethoxy-3-phenylbenzo[b]pyrimido[4,5-f]azocine-12(11H)-one, the first reported example of this ring system.     

Synthesis of 3,4-dihydroisoquinolines using nitroalkanes in polyphosphoric acid

Russian Chemical Bulletin - A new method for the synthesis of 6,7-dimethoxy-3,4-dihydroisoquinoline based on the reaction of 2-(3,4-dimethoxyphenyl)ethan-1-amine (homoveratrylamine) with aliphatic...     

2-Phenyl-4-quinolinone Alkaloids from Casimiroa edulis Llave et Lex (Rutaceae)

 Three new 4-quinolinone alkaloids (5,6-dimethoxy-2-(3-methoxyphenyl)-1H-quinolin-4-one, 5,6-dimethoxy-2-(3,4-dimethoxyphenyl)-1H-quinolin-4-one, 5,6-dimethoxy-2-(2,5,6-trimethoxyphenyl)-1H-quinolin-4-one) were isolated from the leaves of Casimiroa edulis Llave et Lex (Rutaceae) cultivated in Egypt. Their structures were determined by UV/Vis, IR, ¹H and ¹³C NMR, and EI mass spectroscopy. The alkaloids were also detected in the kernels of the seeds.     

2-Phenyl-4-quinolinone Alkaloids from Casimiroa edulis Llave et Lex (Rutaceae)

Summary.  Three new 4-quinolinone alkaloids (5,6-dimethoxy-2-(3-methoxyphenyl)-1H-quinolin-4-one, 5,6-dimethoxy-2-(3,4-dimethoxyphenyl)-1H-quinolin-4-one, 5,6-dimethoxy-2-(2,5,6-trimethoxyphenyl)-1H-quinolin-4-one) were isolated from the leaves of Casimiroa edulis Llave et Lex (Rutaceae) cultivated in Egypt. Their structures were determined by UV/Vis, IR, ¹H and ¹³C NMR, and EI mass spectroscopy. The alkaloids were also detected in the kernels of the seeds. Received May 28, 2001. Accepted (revised) July 24, 2001     

Wacker oxidation methodology for the synthesis of the benzo-fused acetal core of marticin

Methodology for the synthesis of the benzo-fused acetal core of marticin is described in this paper. Condensation of readily available 1-(2-allyl-3,6-dimethoxyphenyl)ethanone with diethyl oxalate under Claisen condensation conditions furnished (Z)-ethyl 4-(2-allyl-3,6-dimethoxyphenyl)-2-hydroxy-4-oxobut-2-enoate. Treatment of this with LiAlH₄ resulted in the formation of the diol, 1-(2-allyl-3,6-dimethoxyphenyl)-3,4-dihydroxybutan-1-one. Conversion of primary alcohol of the diol into the TBDMS ether followed by further reaction with LiAlH₄ and exposure to Wacker oxidation conditions resulted in the formation of (3,6-dimethoxy-9-methyl-10,13-dioxatricyclo[7.3.1.0^2,7]trideca-2,4,6-trien-11-yl)methanol, the core of marticin.     

Total synthesis of lespedezavirgatol

Lespedezavirgatol, a novel 2-phenylbenzofuran compound which was isolated from Lespedeza virgata, was firstly synthesized from pyrogallic acid and 3,4-dimethoxyphenol as starting materials with 8 steps. The key steps for the total synthesis were the selective iodination at 3-position of 1,2-dimethoxy-4-methoxymethoxybenzene and the Sonogashira cross-coupling reaction between 4-iodo-2-methoxybenzene-1,3-diol and 2-ethynyl-3,4-dimethoxy-1-(methoxy-methoxy)-benzene.     

Biological evaluations of fatty acid esters originated during storage of Prasaplai, a Thai traditional medicine

Three fatty acid esters, (E)-4-(3,4-dimethoxyphenyl)but-3-en-1-yl linoleate (1), (E)-4-(3,4-dimethoxyphenyl)but-3-en-1-yl oleate (2), and (E)-4-(3,4-dimethoxyphenyl)but-3-en-1-yl palmitate (3), originated during storage by the interaction of components in Prasaplai, were synthesized. These three artificial esters were subjected to four biological evaluations. All three compounds were active against Mycobacterium tuberculosis H(37)Ra for which compounds 1 and 3 had inhibitory concentration at 200 microg mL(-1) while compound 2 inhibited at 100 microg mL(-1). When all these compounds were subjected to anti-HSV-1 test, compound 2 showed positive activity at 42.6 microg mL(-1) without any cytotoxic activity against human vero cell line while compound 3 had the cytotoxicity to vero cell at IC(50) 38 microg mL(-1). Compound 1 was inactive for this test.     

Synthesis of 6,7-dimethoxy-1-halobenzyl-1,2,3,4-tetrahydroisoquinolines

Some 6,7-dimethoxy-1-halobenzyl-1,2,3,4-tetrahydroisoquinolines were synthesized from 2-(3,4-dimethoxyphenyl)ethylamine and halophenylacetic acids in three steps in good yield.     

Eine neue Synthese von 8-Hydroxy-2-methyl-1,2,3,4-tetrahydroisochinolin

A new Synthesis of 8-Hydroxy-2-methyl-1,2,3,4-tetrahydroisoquinoline Vilsmeier formylation of N-[2-(3,5-dimethoxyphenyl)ethyl]-trifluoroacetamide ( 5 ) yielded the aldehyde 6 , which under mild basic conditions was hydrolyzed to 7 and cyclized to 6,8-dimethoxy-3,4-dihydroisoquinoline ( 3 ). Methylation of 3 and reduction of the double bond in 10 afforded 6,8-dimethoxy-2-methyl-1,2,3,4-tetrahydroisoquinoline ( 11 ). The methoxyl group at C(6) was selectively demethylated and the free hydroxyl group in 12 was phosphorylated to give 13 . Reduction of the latter with potassium in liquid ammonia yielded 8-methoxy-2-methyl-1,2,3,4-tetrahydroisoquinoline ( 2 ), which was demethylated to the title compound 1 .