Ethanolic sodium ethoxide

While the sodium ethoxide solution is cooling, prepare a solution of 7 7 g. of finely powdered iodine in 60 ml. of ether. When this solution is ready, add 9 ml. (9 6 g.) of ethyl malonate to the ethanolic sodium ethoxide solution, mix w ell and then allow to stand for 30-60 seconds not longer) then cautiously add the ethereal solution of the iodine, mixing thoroughly during the addition in order to avoid local overheating by the heat of the reaction. (If, after the ethyl malonate has been added to the sodium ethoxide, a considerable delay occurs before the iodine is added, the yield of the final product is markedly decreased.)... 

Both 2- and 3-nitrothiophenes are reduced by tin and hydrochloric acid to the corresponding aminothiophenes. In contrast to anilines, the free bases are very unstable their salts and acyl derivatives, however, are stable. 2-Aminothiophene can be diazotized and the resulting diazonium salt coupled with /3- naphthol. The chemical instability of aminothiophenes compared with aniline is illustrated by the ring opening of 2-amino-3-ethoxycar-bonylthiophenes (157) with ethanolic sodium ethoxide to give cyanothiolenones (158) <75JPR861). 

Furthermore they claimed that the dichloromethyhndolenine 17 could be converted into the quinohne 18 by hot ethanolic sodium ethoxide. They also reported other similar cases of ring expansion of the dichloromethyl bases, with loss of hydrogen chloride, on further treatment with sodium ethoxide (cf. ref. 67). They considered that chloroform acted like a simple alkyl halide giving jS-alkylation of the... 

The reaction of ethyl 3-oxobutanoate with 4-aryltetrahydropyridazine-3,6-di(Mie 3-hydrazones 60a-d afforded the corresponding hydrazonobutanoates 61a-d. When heated with ethanolic sodium ethoxide, compounds 618-d cyclized to the sodium derivatives 62a-d which, upon acidification, gave the respective pyrazol-3-one derivatives 63a-d (97JHC389) (Scheme 19). 

This four-atom replacement was observed in some reactions of uracil derivatives, containing at position 5 a substituent with the CCCN moiety. Treatment of the Z-isomer 5-(2-carbamoylvinyl)-l,3-dialkyluracil with ethanolic sodium ethoxide gave in good yield 3-ethoxycarbonylpyridin-6(lf/)-one (84%) together with 3-A-methylcarbamoyl)pyridin-6-(l7 )-one (10%) (85JOC1513) (Scheme 26). The reaction involves an initial attack of the terminal amino group of the side-chain on position 6 of the uracil molecule. C-6-N-1 bond fission and N-C bond formation yield the pyridin-6(l//)-one. A subsequent attack of the ethoxide ion on the carbonyl groups of the side-chain yields both pyridin-2-one derivatives (Scheme 26). Similar results were obtained with the -isomer. 

The action of triethylamine or 4-methylmorpholine on the imidazole derivatives 1 results in the formation of 4,5-dihydro-l/f-l,2-benzodiazepines 2, which eliminate imidazole on heating with ethanolic sodium ethoxide to give H-, 2-benzodiazepines 3.121 Details for compound 3 (R1 = Ph, R2 = Me) only were reported it was stated that other derivatives were obtained similarly but details were not given. 

Spectrophotometry has been used in the measurement of the dissociation constants of some weak acids using the color of the ion as an indicator. The dissociation constant of tris-(/>-nitrophenyl)-methane in ethanolic sodium ethoxide at 25° is 3.66 X 10-18.848 Another method makes use of the difference in optical rotation between menthol and sodium mentholate to find the position of the equilibrium 844... 

Thiourea and its /V-substituted derivatives readily reacted with EMME in hot ethanolic sodium ethoxide to yield 2-thiopyrimidine-5-carboxylates (219) (42JA794 56JA5294), With N-substituted thiourea, as in the case of -substituted urea, the primary amino group was first involved in the reaction. 

The preparation described here of 3-cyclopentene-1-carboxylic acid from dimethyl malonate and cis-1,4-dichloro-2-butene is an optimized version of a method reported earlier3 for obtaining this often used and versatile building block.6 The procedure is simple and efficient and requires only standard laboratory equipment. 3-Cyclopentene-1-carboxylic acid has previously been prepared through reaction of diethyl malonate with cis-1,4-dichloro(or dibromo)-2-butene in the presence of ethanolic sodium ethoxide, followed by hydrolysis of the isolated diethyl 3-cyclopentene-1,1-dicarboxylate intermediate, fractional recrystallization of the resultant diacid to remove the unwanted vinylcyclopropyl isomer, and finally decarboxylation.2>7 Alternatively, this compound can be obtained from the vinylcyclopropyl isomer (prepared from diethyl malonate and trans-1,4-dichloro-2-butene)8 or from cyclopentadiene9 or cyclopentene.10 In comparison with the present procedure, however, all these methods suffer from poor selectivity, low yields, length, or need of special equipment or reagents, if not a combination of these drawbacks. 

The Cs atom of (I 0 is asymmetric. The D- and L-forms, as well as the racemate of (IV), have been prepared by heating L-, D- or DL-N -carbethoxy-asparagine, respectively, with ethanolic sodium ethoxide [74]. It was found that... 

Substitution of the halogen in 387 and 388 by nucleophiles has also been reported (81M245 83AP697), as has the cyclization of 389 into 390 (83G219). Ethyl l,5-diaryl-3-trifluoromethyl-4-oxopyrazolo[3,4-c/] pyridazin-7-ylacetate afforded bicyclic 5(5-oxopyrazol-3-yl)pyrazolines upon treatment with ethanolic sodium ethoxide (88JHC134). 

Thus, methyl (5-acetyl-2-thienyIthio)acetate (62) was prepared by acetylation of 61. Addition of a second acetyl group in the presence of excess AlClj led to methyl (3,5-diacetyl-2-thienylthio)acetate (63), which, on heating in ethanolic sodium ethoxide yielded about 95% of 5-acetyl-3-methylthieno[2,3-6]thiophene-2-carboxylic acid (64) reduction of acid 64 resulted in 5-ethyl-3-methylthieno[2,3-6] ophene 2-carboxylic add (65), identical with the acid obtained by cyclization of methyl (3-acetyl-5-ethyl-2-thienylthio)acetate. Decarboxylation of acid 64 gave 5-acetyl-3-methylthieno[2,3-6]thiophene (66) [Eq. (25)1. 

Aldehydo nitriles are readily available and can be used to prepare 4-amino-6-unsubstituted pyrimidines carrying one or more substituents in any of the other positions. Equivalents of the formyl group are also often used, for example, a 3-ethoxy-, 3-amino-, or 3-haloacrylonitrile. Most syntheses with /3-keto nitriles are carried out with equivalents thereof Such equivalents are /3-substituted /3-alkoxy-, /3-amino-, or /3-haloacrylonitriles. /3 -Ester nitrile reactions are also well established. Malononitriles and substituted malononitriles react readily with thiourea and N-substituted thioureas in refluxing ethanolic sodium ethoxide to form pyrimidine-4,6-diamines. An example is the reaction of N2-malononitrile 680 with N2-thiourea 681 to give N4- 4,6-diamino-2-(l//)-pyrimidinethione 682 which was then used in the synthesis of Ns-labeled adenine derivatives <2001JOC5463>. 

Butler and co-workers studied the quatemisation of 3,5-diaryl-l,2,4-thiadiazoles 77 with trimethylsilylmethyl triflate at 40 °C and observed reaction at N-2 to give salt 78. Desilyation of 78 with caesium fluoride resulted in ring expansion to 2ff-l,3,5-thiadiazines 79 which on heating in ethanolic sodium ethoxide gave 2,4-... 

Azoloazines are synthesized by this route, as indicated in CHEC-II <1996CHEC-II(7)431>. Reaction of 251 with urea or thiourea in refluxing ethanolic sodium ethoxide afforded 252 (Equation 28). 

Diethyl ethylidenemalonate has been prepared by heating acetaldehyde, diethyl malonate, and acetic anhydride 2 3 by heating the same reagents plus zinc chloride 4 by treating acetaldehyde and diethyl malonate with sodium ethoxide or piperidine 6 and by heating diethyl malonate, ethylidene bromide, and ethanolic sodium ethoxide.6... 

Ethoxyacetylene reacts with refluxing ethanolic sodium ethoxide to give a 44% yield of triethyl orthoacetate [128], In addition, aldoximes and ketoximes react with ethoxyacetylene to give orthoacetic acid derivatives shown in Eqs. (35) and (36) [129]. More work is required to establish the generality of this reaction. 

Reaction of TV,TV-dimethyl-TV-allyl-2,2,3,3-tetrachlorobutylammonium bromide with ethanolic sodium ethoxide to give trialkyl orthopropiolate [177]. 

Reaction of 1,2-diiodoacetylene with ethanolic sodium ethoxide to form triethyl iodoorthoacetate in low yield [205]. 

Recently, an experimental reappraisal of this rearrangement was reported, in which cubyl phenyl ketone tosylhydrazone (1) was thermolyzed in an ethanolic sodium ethoxide solution to give a good yield of a 1.5 1 mixture of 9-ethoxy-9-phenylhomocubane (3) and 9-ethoxy-l-phenylhomocubane (4).3 In addition, photolysis (mercury arc, Pyrex filter) of cubylphenyldi-azomethane (2) in ethanol also produced a similar result.3... 

Methyl-2-phenylindolizine reacts with ethoxalyl chloride to give the 1,3-diethoxalyl derivative (17). Heating in ethanolic sodium ethoxide converts 17 partly into cycl[3,2,2]azine (lu) and partly into the salt of a hydroxycycl[3,3,2]azinone (45a) (Section IV).16... 

Cyclization of cr-aryl-o-nitroacetanilides 56 to quinoxaline A-oxides has been reported independently by three groups.66-68 Thus treatment with ethanolic sodium ethoxide of 56 (R=R =H R2=Ph), synthesized from o-nitroaniline and PhCH2COCl, gives l,2-dihydro-2-oxo-3-phenyl-quinoxaline 4-oxide (57 R=R =H, R =Ph). 

The amino compounds form salts and acylamino derivatives which are considerably more stable. Interesting ring-opening reactions can be initiated by proton loss from the amino group. Thus, 2-amino-3-ethoxycarbonylthiophenes (383) with ethanolic sodium ethoxide give cyanothiolenones (384) (75JPR86). In a similar sequence 2 amino-3-acetylfurans (385) are converted into 3-cyano-2-methylpyrroles (386) by aqueous ammonia (78JOC3821). 

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