P-Methoxyphenyl ester

More conventional liquid-liquid biphasic conditions have been also conveniently employed to increase the efficiency of the photo-Fries reaction. For instance, p-methoxyphenyl esters of a, 5-unsaturated carboxyhc acids (30) undergo photochemical rearrangement, followed by basic cyclization to give... 

For imines, a-imino esters with an N-p-methoxyphenyl substituent (21b) also reacted with Danishefsky s diene in the presence of 10 mol% of CUCIO4-T0I-BINAP to give the corresponding adduct in high yield with good enantiomeric excess (Scheme 5.10). Remarkably, reverse enantioselectivity was observed when the a-imino esters 21a and 21b were used. This notable selectivity was explained by as-... 

According to results from laser flash photolysis, the p-(methoxyphenyl) sulfanyl radical adds exclusively to the central atom in of 2,4-dimethylpenta-2,3-diene (If) with a rate constant of 1.1 x 10s M-1 s-1 (23 1 °C) (Scheme 11.6) [45], A correlation between the measured rate constants for addition of para-substituted arylsulfanyl radicals to allene If was feasible using Brown and Okomoto s o+ constant [46], The p+ value of 1.83, which was obtained from this analysis, was interpreted in terms of a polar transition state for C-S bond formation with the sulfanyl radical being the electrophilic part [45]. This observation is in agreement with an increase in relative rate constant for phenylsulfanyl radical addition to 1-substituted allene in the series of methoxyallene lg, via dimethylallene Id, to phenylsulfanylallene lh, to ester-substituted 1,2-diene li (Table 11.2). 

Ar = p-methoxyphenyl (Bruice and Pandit, 1960). The calculation (Page, 1973) is similar to that for phenyl phthalate (note j), except that a factor of 6.3 x 10-2 is used for the lower reactivity of the unsaturated ester... 

The following compounds are unaffected by bis(p-methoxyphenyl) telluroxide dithi-olanes, enamines, aldehydes, ketones, alcohols, pyrroles, indoles, amino acids, aromatic amines, monohydroxyarenes, esters, hindered thiocarbonates, isonitriles, oximes, arylhy-drazones, sulphides, and selenides. ... 

Like p-methoxyphenyl teUuroxide, tellurinic anhydrides do not affect phenols but oxidize hydroquinones to the corresponding quinones, and oxidize thiols, thioesters, thioamides and phosphines to disulphides, esters, nitriles and phosphine oxides. 

Model compound studies indicated that both the nature of the base, the nature of the alkyl ester and the amide group exerted pronounced effects on the observed imidization rates [59]. As illustrated in Table 6, the imidization rate of monomethyl p-methoxyphenyl phthalamide tracks the general basicity of the... 

Table 6. Effect of base strength on the imidization rate of monomethyl ester p-methoxyphenyl phthalamide at 23.3 °C.

Boc,245 /-butyl ester,246 trityl ether247 and even tris(p-methoxyphenyl)methyl ether.248 The oxidation-sensitive PMB normally resists the action of PCC,249 as well as the sulfur-containing protecting groups dithioacetals250 and mono-thioacetals.251... 

Indanyl)-phenol 16 was obtained by reacting p-methoxy-phenyl-acetic acid ethyl ester with benzylchloride to form a-benzyl-p-methoxyphenyl ethyl acetate, saponification into the acid, conversion of the acid with thionylchloride into the chloride, cyclization to 2-p-methoxy-phenyl-l-indanone, NaBH4 reduction to 2-p-methoxyphenyl-l-indanole, dehydration with p-toluene-sulphonic acid in toluene to 2-p-methoxyphenyl-indene, catalytic hydrogenation to 2-p-methoxyphenyl-indene, and treating the ether with HBr [Eq. (5)]. 

R)-3-AMINO-3-(p-METHOXYPHENYL)PROPIONIC ACID (1(2H)-Pyrlmldlnecarboxyllc acid, 2-(l,1-dimethylethyl)-3,4-dlhydro-4-oxo-, methyl ester, (R)- or (S)-)... 

Asymmetric Aza-Henry Reactions of Nitronates with Imines. Although the Henry reaction and its aza-analogs are powerful C-C bond-forming reactions, there are few reports of catalytic asymmetric versions of these reactions. The cir-DiPh-Box copper complexes are excellent catalysts for highly diastereo and enantioselective aza-Henry reactions of a variety of trimethyl-silylnitronates with Af-(p-methoxyphenyl)-a-imino-esters (eq 3). The use of an A-(/ -methoxyphenyl) group for protection prevents undesirable side reactions and can be easily removed. The aza-Henry reaction products can be further derivatized to the corresponding a,3-diamino acids whose syntheses have rarely been reported. 

As discussed briefly in Section II,A, dimethy l-(p-methoxyphenyl)aziridine-2,3-dicarboxylate (6) undergoes a stereospecific ring opening generating ester-... 

Diltiazem hydrochloride has also been known as (+)-cis-3-(acetyloxy)-5-[2-(dimethylamino)ethylJ-2,3-dihy-dro-2-(4-methoxyphenyl)-1,5-benzothiazepin-4(5H)-one monohydrochloride and (+)-5-[2-(dimethylamino)ethyl]-cis-2>3-dihydro-3-hydroxy-2-(p-methoxyphenyl)-1,5-benzothia-zepin-4(5H)-one acetate (ester) monohydrochloride. 

METHYL CARBAMATE FORMATION VIA MODIFIED HOFMANN REARRANGEMENT REACTIONS METHYL N-(p-METHOXYPHENYL)CARBAMATE (Carbamlc acid, (4-methoxyphenyl)-, methyl ester)... 

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