A-Dimethylation

PPFA jV,A -dimethyl-l,2-(diphenylphosphino)ferrocenyle hylamine py pyridine... 

A solution of 4% aq. H2SO4, (301) was heated to 50"C over 30-60 min. Nitrogen was bubbled through the solution during this time. 4-(Cyano-methyl)phenylhydrazine hydrochloride (1080g, 4.77 mol) was added as a solid to the heated mixture. After it had dissolved, A,A-dimethyl-4,4-dimethoxy-butanamine (965 g, 5.98 mol) was added over a period of 30 min. The mixture was then heated at reflux for 2 h. The reaction mixture was cooled and diluted with portions of 30%o aq. NH4OH (21 total) over 0.5 h at a rate to maintain the temperature at 25-30°C. The product was then extracted into isopropyl acetate (3 x 101). The solution was concentrated to 31 which led to a precipitate which was isolated by filtration and washed with cold isopropyl acetate to give 827.4 g (76%) of product. 

T etrahydrocarbazol-9-ylmagnesium bromide N,A -Dimethyl-3-chloropro- 50 panaminc [12]... 

Loperamide. 4-(4-Chlorophenyl)-4-hydroxy-A7,A/-dimethyl- 7, 7-diphenyl-l piperidinebutanamide monohydrochloride [43552-83-5] (Imodium) (14) is practically iasoluble ia water (0.002%) at physiological pH. Its crystals are not affected by light and it is not hygroscopic. It may be synthesized (12). 

Pigment Blue 1 [1325-87-7] 42595 2 triarylcarbonium PTMA salt (Victoria Blue B) condensation of 4,4 -bis-A/A/-dimethyl aminoben2ophenone with /V-ethyl-1-naphthylamine, followed by oxidation and salt formation... 

A7, A/-dimethyl-2-methylcarbamoyloxyimiao-2-(methyl thio)acetamide Vydate / ox amyl iasecticide... 

Aqueous salt solutions such as saturated 2inc chloride [7646-85-7] or calcium thiocyanate [2092-16-2] can dissolve limited amounts of cellulose (87). Two non-aqueous salt solutions are ammonium thiocyanate [1762-95-4]— uoamonia. and lithium chloride /744Z-4/A/—dimethyl acetamide [127-19-5]. Solutions up to about 15% can be made with these solvents. Trifluoroacetic acid [76-05-17—methylene chloride [75-09-2] and /V-methy1morpho1ine N-oxide [7529-22-8]—(92—94) are two other solvent systems that have been studied (95). 

Another appHcation of 4-chlorophenol is in the synthesis of a dmg, ethyl a, a-dimethyl-4-chlorophenoxy acetate [637-07-0] (60), used as a cholesterol-reducing agent. This synthesis involves reaction with acetone and chloroform, followed by ethanol esterification. 

Amino-pyridazines and -pyridazinones react with monomethyl- or iV,A-dimethyl-formamide and other aliphatic amides in the presence of phosphorus trichloride, thionyl chloride, phosgene or benzenesuUonyl chloride to give mono- or di-alkylaminomethyl-eneamino derivatives. The same compounds can be prepared conveniently with A,iV-dimethylformamide dimethyl acetal in high yield (Scheme 50). 

Alkynic esters react with nitrile oxides in a pH dependent reaction to product isoxazolin-5-ones (Scheme 145) (71JCS(C)86). Alkynic ethers also react with benzonitrile oxide to produce an isoxazole-ether which on treatment with HCl or HBr gave an isoxazolinone (Scheme 145) (63CB1088,58MI41600). The reaction of benzonitrile oxide with dimethoxyketene yielded a dimethyl acetal which was split with acid into the isoxazolinone (Scheme 145) (59G15H). 

M HCl, aq. THF, 50°, 6-8 h, 95% yield.An attempt to cleave the MOM group with acid in the presence of a dimethyl acetal resulted in the cleavage of both groups, probably by intramolecular assis-... 

DMSO, H2O, dioxane, reflux, 12 h, 65-99% yield.These conditions cleave a dimethyl ketal in the presence of a r-butyldimethylsilyl ether. 

From a dimethyl acetal BCl3 Et20, —45°, CH3SH, 73% yield. ... 

A,A-Dimethyl-/7-nitrosoaniline hydrochloride [42344-05-8] M 186.7, m 177 . Crystd from hot water in the presence of a little HCl. 

MA -Dimethylamino)phenyl]-2-ethylpropenal (5) was produced by reaction of A, A -dimethyl-aniline (/) with 2-ethyl-3-ethoxyacrolein (2) in the presence of phosphorus oxytrichloride. 

---