5.6- dimethoxy-2-methyl- -chloride

Oxo-3,4-dihydro-2-quinoxalinecarboxylic acid (36, R = OH) gave 3-oxo-3,4-dihydro-2-quinoxalinecarbonyl chloride (36, R = Cl) (neat SOCI2, reflux, 1 h 6,7-dimethoxy -methyl-3-oxo-3,4-dihydro-2-quinoxalinecarboxylic acid (37, R = OH) gave 6,7-dmieihoxy-4-methyl-3-oxo-3,4-dihydro-2-quinoxalinecarbonyl chloride (37, R = C1) (likewise >91%). ... 

DIHYDRO-3-FURANONES 2,2-Dimeth-oxymethyl-1,3-dithiane. DIHYDRO-y-PYRONES 2,2-Dimethoxy-methyl-1,3-dithiane. vic-DIOLS Titanium(III) chloride. o-DIKETONES Potassium permanganate-Acetic anhydride. Ruthenium tetroxide. 

A preliminary investigation of the efficacy of the synthesis of 4-(4,6-dimethoxy-l,3 5-triazin-2-yl)-4-methylmor-pholinium (DMTMM) chloride <1998JOC4248> evidenced the formation of methyl chloride in a demethylation side reaction, which decreased the yield and caused contamination of the final products (Scheme 1) <1999TL5327>. The demethylation product from DMTMM was isolated and identified unequivocally as 4-(4,6-dimethoxy-l,3,5-triazin-2-yl)morpholine (DMTM) by X-ray diffraction. 

Methyl-1,2-dihydropapaverine (175, R = OMe) rearranges to the 2-methyl-3-(3,4-dimethoxybenzyl)-6,7-dimethoxy-3,4-dihydroisoquinolin-ium salt (176, R = OMe) under very mild conditions (treatment with 2% hydrochloric acid). A similar rearrangement of l-(3,4-methyl-enedioxybenzyl) - 2 - methyl - 6,7 - dimethoxyisoquinoline (175, R, R = —O—CHj—O—) affords 3-(3,4-methylenedioxybenzyl)-2-methyl-6,7-di-methoxy-3,4-dihydroisoquinolinium chloride (176, R, R = O—CHj—O—) (256). The reaction was shown to be an allylic rearrangement with internal return (275,275). 

To the reduction mixture was then added 3.5 g of 5% palladium on carbon catalyst and the mixture was hydrogenated under a hydrogen pressure of 50 psi at room temperature for 12 hours. The catalyst was removed by filtration and the filtrate was evaporated to a small volume. The concentrated filtrate was dissolved in diethyl ether and the ethereal solution was saturated with anhydrous hydrogen chloride. The reduction product, 3,4-dimethoxy-N-[3-4-methoxyphenyl)-1 -methyl-n-propy 11 phenethylamine was precipitated as the hydrochloride salt. The salt was filtered and recrystallized from ethanol melting at about 147°C to 149°C. 

Two approaches for the synthesis of allyl(alkyl)- and allyl(aryl)tin halides are thermolysis of halo(alkyl)tin ethers derived from tertiary homoallylic alcohols, and transmetalation of other allylstannanes. For example, dibutyl(-2-propenyl)tin chloride has been prepared by healing dibutyl(di-2-propenyl)stannane with dibutyltin dichloride42, and by thermolysis of mixtures of 2,3-dimethyl-5-hexen-3-ol or 2-methyl-4-penten-2-ol and tetrabutyl-l,3-dichlorodistannox-ane39. Alternatively dibutyltin dichloride and (dibutyl)(dimethoxy)tin were mixed to provide (dibutyl)(methoxy)tin chloride which was heated with 2,2,3-trimethyl-5-hexen-3-ol40. 

The three-necked flask is charged with 750 ml. of formamide, 25 ml. of water, and 50 g. of ammonium chloride (Note 2). The mixture is heated to 180-190° in an oil bath, and 400 g. (3.02 moles) of 4,4-dimethoxy-2-butanone (Note 3) is added dropwise with stirring over the course of 6 hours (Note 4). The flow of cooling water in the reflux condenser should be adjusted to a rate such that the methanol and methyl formate formed during the reaction distil out (Note 5). After all the acetal has been added, heating is continued for 1 hour (Note 6). The mixture is allowed to cool and is poured into 1 1. of IN sodium hydroxide. The resultant solution is extracted with chloroform in a liquid-liquid extractor for 24 hours. The chloroform is separated, dried over sodium sulfate, and removed by distillation through a short column on a steam bath. 

Dimethoxy-6-methyl-7-nitro-5-quinoxalinecarbonyl chloride (88, R = Cl) gave 2,3-dimethoxy-6A(A(-trimethyl-7-nitro-5-quinoxalinecarboxamide (88, R= NMe2) (MejNH, THE, 20°C, 19 h >95%), V-(tert-butoxycarbonyl-methyl)-2,3-dimethoxy-6-methyl-7-nitro-5-quinoxalinecarboxamide (88, R = NHCHj CO2BU ) (Bu 02CCH2NH2-HC1, EtaN, THE substrate/THEj drop-wise, N2, 5 min then 20°C, 24 h 77%), and a variety of analogs similarly. ... 

Dimethoxy-6-methyl-7-nitro-5-quinoxalinecarboxylic acid (38, R = OH) gave 2,3-dimethoxy-6-methyl-7-nitro-5-quinoxalinecarbonyl chloride (38, R = Cl) (neat SOCl2, reflux, 20 h 96%)506... 

Dimethoxy-4-methyl-3-oxo-3,4-dihydro-2-quinoxalinecarbonyl chloride (92, R = Cl) gave the corresponding carbonyl azide (92, R = N3) (NaN3, AcMe, 0°C, 2 h 78%).934... 

All solvents used for general applications were of reagent grade. For special purposes, purification of solvents was effected using standard procedures. All other reagents were used as supplied commercially except as noted. A solution of chloromethyl methyl ether (6 mmole/mL) in methyl acetate was prepared by adding acetyl chloride (141.2 g, 1.96 mol) to a mixture of dimethoxy methane (180 mL, 2.02 mol) and anhydrous methanol (5.0 mL, 0.12 mol).20 The solution was diluted with 300 mL of 1,1,2,2-tetrachloroethane and used as a stock solution for the chloromethylation experiments. 

Dimethoxybenzoyl chloride Benzoyl chloride, 2,3-dimethoxy- (9) (7169-06-4) 2-Amino-2-methyl-1-propanol 1-Propanol, 2-amino-2-methyl- (8,9) (124-68-5) 2,2 -Dimethoxy-6-(4 ,4 -dimethyloxazolinyl)biphenyl Oxazole, 2-(2 ,6-dimethoxy[1,1-biphenyl]-2-yl)-4,5-dihydro-4,4-dimethyl- (9) (57698-39-7)... 

Mercapto-l /7-l,2,4-triazol-3 -yl-isoquinolinium chlorides 438 react with 1,2-dibromoethane to produce a variety of substituted 6,7-dimethoxy-3-methyl-W-(5, 6 -dihydrothiazolo[3,2-3][l,2,4]triazol-2 -yl)isoquinolinium bromides 439 (Equation 96) <2003JHC1041>. 

An attempt to methylate the diketone (97) with methanolic hydrogen chloride gave the dimethoxy derivative (98), presumably by alkylation of the j8-dicarbonyl system by the activated aromatic nucleus. The possibility therefore exists of synthesizing polymethoxy derivatives of dibenzothiophene by the 2-chlorocyclohexanone route (Section IV, A), using this modification of the ring-closine step. 

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