Methoxy derivative

Many of the pigments carry a nitro group ia the diazonium component, usually ia the ortho position (R = NO2). Among the acetoacetaryUde components the o-methoxy derivative (R2 = OCH, R3 = H) is one of the most important ia the production of azo pigments. The colors of these pigments range from red to green-shade yellows. Commercially important products ate shown ia Table 3. 

The kinetics of formation and hydrolysis of /-C H OCl have been investigated (262). The chemistry of alkyl hypochlorites, /-C H OCl in particular, has been extensively explored (247). /-Butyl hypochlorite reacts with a variety of olefins via a photoinduced radical chain process to give good yields of aUyflc chlorides (263). Steroid alcohols can be oxidized and chlorinated with /-C H OCl to give good yields of ketosteroids and chlorosteroids (264) (see Steroids). /-Butyl hypochlorite is a more satisfactory reagent than HOCl for /V-chlorination of amines (265). Sulfides are oxidized in excellent yields to sulfoxides without concomitant formation of sulfones (266). 2-Amino-1, 4-quinones are rapidly chlorinated at room temperature chlorination occurs specifically at the position adjacent to the amino group (267). Anhydropenicillin is converted almost quantitatively to its 6-methoxy derivative by /-C H OCl in methanol (268). Reaction of unsaturated hydroperoxides with /-C H OCl provides monocyclic and bicycHc chloroalkyl 1,2-dioxolanes. 

The O-alkyl derivatives of those A-oxides, which exist partly or entirely as (V-hydroxy tautomers, may be made by primary synthesis (as above) or by alkylation. Thus, 5,5-diethyl-1-hydroxybarbituric acid (936 R = H) with methyl iodide/sodium ethoxide gives the 1-methoxy derivative (936 R = Me) or with benzenesulfonyl chloride/ethoxide it gives the alkylated derivative (936 R = PhS02) (78AJC2517). 

Oxo substituents are, in a few cases, methylated with diazomethane to give methoxy derivatives in addition to the major iV-methylation, and oxo groups in the 3-deazaflavins have been acylated. 

Methyl-2,l-benzisoxazole and its 6-methoxy derivative are both readily brominated at the 3-methyl group with NBS (79TL4687, 74RTC139). The 4-methoxy isomer gives only the 7-bromo compound unless excess of the reagent is used, when 7-bromo-3-(bromomethyl)-2,l-benzisoxazole is obtained in 52% yield (74RTC139). However, there is... 

The Schiff base intermediate (57) permits the oxidative formation of an imino intermediate which can then be converted to the 6a-methoxy derivative (Scheme 45) (76MI51100). 

S. Henningsii (S. Africa). Two crystalline alkaloids (1) 23 28 5 2> m.p. 280-5-282°, [a]], ° — 80° (EtOH) contains one methoxyl, but no methylimino group and is possibly phenolic (2) 24 3305 2> m.p. 214-5-215°, contains two methoxyl groups and gives a violet coloration with Frohde s reagent. The alkaloids are possibly mono-and di-methoxy derivatives of the same parent base. Amorphous alkaloids are also present and possibly a third crystalline base (Rindl, S, Afr. J. Sci., 1929, 26, 50 Trans. Boy. Soc. S, Africa, 1931, 20, 59 (with Sapiro), ibid., 1936, 23, 361). 

The authors point out that erythrophleie acid may be a methoxy-derivative of cassaic acid,... 

The pyrimidine compounds are known to undergo a rearrangement of the 0-alkyl derivatives to the iV-alkyl ones. The methoxy derivatives of 1,3,5-triazine display a similar behavior. On applying methyl iodide to 2,4-dimethoxy-l,3,5-triazine one of the methyl groups is shifted giving rise to l-methyl-4-methoxy-derivative (22). This compound was also obtained by methylation of 4-methoxy-2-oxo-1,2-dihydro-1,3,5-triazine (18) with diazomethane. At higher temperature (100°C) in presence of methyl iodide a shift of both methyl groups takes place and methiodide is formed simultaneously (23). Similarly,... 

Hydroxypyridine 1-oxide is insoluble in chloroform and other suitable solvents, and, although the solid-state infrared spectrum indicates that strong intermolecular hydrogen bonding occurs, no additional structural conclusions could be reached. Jaffe has attempted to deduce the structure of 4-hydroxypyridine 1-oxide using the Hammett equation and molecular orbital calculations. This tautomeric compound reacts with diazomethane to give both the 1- and 4-methoxy derivatives, " and the relation of its structure to other chemical reactions has been discussed by Hayashi. ... 

A few other aldehydes have been used in the reaction, either under normal or pseudo-physiological conditions. Of these, glycolalde-hyde, 5-hydroxypentanal, phenylacetaldehyde, and benzalde-hyde condense readily, but hydroxy and methoxy derivatives of these aromatic aldehydes give the product in poor yield,presumably due to their instability, as evidenced by their tendency to undergo self-condensation in acid solution. Reaction with phthaldehydic acids, such as opianic acid, proceeded readily, whereas reaction with chloral did not occur,... 

Dihydro-j8-carboline itself, the parent compound of the group, whose original preparation from A -formyltryptamine was doubtful, has now been describedand characterized. Its 9-methyl and 6-methoxy derivatives have also been prepared. 

R = OCH3) into isoevodiamine and its 5-methoxy derivative (362a), respectively (cf. 113 362a 362). 

The order NO2 > Cl, which is known for the reactions of nitro-activated aromatic compounds, is also found for pyridine and quinoline derivatives. In the reaction of 2-chloro-4-nitroquinoline with methoxide ion, only the 4-methoxide derivative is formed, as shown by gas-chromatography, whereas 2,4-dichloroquinoline yields a mixture of the isomeric chloro-methoxy derivatives in comparable amounts. ... 

Methoxylation of 2,5- and 2,3-dibromopyrazines provides the basis for a comparison of ortho and para direct deactivation (Section II, E, 2, e) in the mono-methoxy derivatives such as 198 and 199. Pyrazine derivatives are discussed in Sections II, C and II, D. 

Reaction of 2,4,7-trichloroquinoline with sodium methoxide (65°, 30 min) yielded an equal mixture of 2,7-dichloro-4-methoxy- (40%) and 4,7-dichloro-2-methoxy-derivatives (31%). The activating effect of the chloro groups is evident from the inertness of 4-chloro-quinoUne to methoxide ion at 65°. Alteration of the relative reactivity by cationization of the azine ring is again noted here in the acid-catalyzed hydrolysis (dilute HCl, 100°, 1.5 hr) of the trichloro compound to give 72% of the 2-hydroxylation product.Similarly, acid-hydrolysis of the alkoxy group proceeds much more readily in 2-ethoxy-4-chloro- than in 4-ethoxy-2-chloro-quinoline. ... 

Quite unstable. The yield was obtained by leading it to W-acetyl-1-methoxy derivative by reacting with diazomethane, followed by treatment with acetic anhydride. 

We first tried to prepare 1-hydroxyyohimbine (23) and its derivatives. With 23 in hand (as described in Section II.D), its methylation with CH2N2 is carried out to provide 1-methoxy derivative 304 (77%) (Scheme 47). Utilizing K2CO3 as a base in DMF, allyl bromide, butyl iodide, and p-nitrobenzyl bromide react successfully with 23, resulting in the formation of 305 (93%), 306 (99%), and 307 (90%), respectively. All of these compounds, including 23 itself, are found to exhibit potent Q 2-blocking activity (2001H1237), and the details will be reported in due course. 

Table IV. NMR Spectroscopic Comparison Between Coralyne-13-Olate 109, 13-Methoxy Derivative 112, and the Alkaloid 117...

Table V. UV Spectra oe Coralyne-13-Olate 109, its Hydrochloride Salt 109 HCl, AND ITS Methoxy Derivative 112...

Flash vacuum thermolysis (FVT) of 2-substituted 4//-pyrido[l,2-n]pyrimidin-4-ones 126 above 800 °C afforded (2-pyridyl)iminopropadie-none (130) (99JCS(P2)1087). These reactions were interpreted in terms of reversible ring opening of 4//-pyrido[l,2-n]pyrimidin-4-ones to imidoyl-ketenes 127. A 1,5-H shift in 127 generated the N(l)H-tautomeric methylene ketene 128, in which facile elimination of HX took place via a six-membered cyclic transition state 129 to yield 130. In the case of 2-methoxy derivative 126 (X = OMe) another competing pathway was also identified at lower temperature, which resulted in the formation C3O2 and 2-methylaminopyr-idine via mesoionic isomer 131 (Scheme 9). The products were identified by IR spectroscopy. 

---