Acetaldehyde, Bromo

Acetaldehyde, bromo-, diethyl ACETAL, 23, 8 24, 3 Acetamide, 25, 36 /i-Acetaminobenzenesulfinate, SODIUM, 22, 31... 

A -(2 2-Diethoxyethyl)anilines are potential precursors of 2,3-unsubstituted indoles. A fair yield of 1-methylindole was obtained by cyclization of N-inethyl-M-(2,2-diethoxyethyl)aniline with BFj, but the procedure failed for indole itself[2], Nordlander and co-workers alkylated anilines with bromo-acetaldehyde diethyl acetal and then converted the products to N-trifliioro-acetyl derivatives[3]. These could be cyclized to l-(trifluoroacetyl)indoles in a mixture of trifluoroacetic acid and trifluoroacetic anhydride. Sundberg and... 

Relatively little is known concerning the substitution reactions of the carbolines. The most studied reaction is that of nitration. Nitration of l-methyl-j8-carboline gave two mononitro derivatives. The highermelting isomer, which was formed predominantly (57% yield), was shown to be 6-nitro-l-methyl-j8-carboline (253 R = CH3) by its conversion into 6-bromo-l-methyl-j5-carboline the latter was synthesized unambiguously from 5-bromotryptophan and acetaldehyde. The lower melting isomer, recovered in 20% yield, was presumed to be the 8-nitro derivative (254), although this was not established. Nitration of j8-carboline with concentrated nitric acid at 35° has been reported to yield 6-nitro-j3-carboline (253 R = H) as the sole product. Only the 6-nitro derivatives (255) were isolated on nitration... 

Phenyl-ethyl alcohol can be prepared by numerous methods, several of which are the subject-matter of patents. It may be prepared, for example, by the conversion of phenyl-bromo-lactic acid into phenyl-acetaldehyde, and then reducing this body with sodium. Or it may be prepared by reducing phenyl-acetic esters with sodium and absolute alcohol in the folio-wing manner —... 

To now solve the problem posed at the beginning of this section, it s possible to use a halo alcohol in a Grignard reaction by employing a protection sequence. For example, we can add 3-bromo-l-propanol to acetaldehyde by the route shown in Figure 17.9. 

Diels-Alder cycloaddition of 5-bromo-2-pyrone with the electron-rich tert-butyldi-methylsilyl (TBS) enol ether of acetaldehyde, using superheated dichloromethane as solvent, has been investigated by Joullie and coworkers (Scheme 6.90) [188]. While the reaction in a sealed tube at 95 °C required 5 days to reach completion, the anticipated oxabicyclo[2.2.2]octenone core was obtained within 6 h by microwave irradiation at 100 °C. The endo adduct was obtained as the main product. Similar results and selectivities were also obtained with a more elaborate bis-olefin, although the desired product was obtained in diminished yield. Related cydoaddition reactions involving 2-pyrones have been discussed in Section 2.5.3 (see Scheme 2.4) [189]. 

The results of the olefin oxidation catalyzed by 19, 57, and 59-62 are summarized in Tables VI-VIII. Table VI shows that linear terminal olefins are selectively oxidized to 2-ketones, whereas cyclic olefins (cyclohexene and norbomene) are selectively oxidized to epoxides. Cyclopentene shows exceptional behavior, it is oxidized exclusively to cyclopentanone without any production of epoxypentane. This exception would be brought about by the more restrained and planar pen-tene ring, compared with other larger cyclic nonplanar olefins in Table VI, but the exact reason is not yet known. Linear inner olefin, 2-octene, is oxidized to both 2- and 3-octanones. 2-Methyl-2-butene is oxidized to 3-methyl-2-butanone, while ethyl vinyl ether is oxidized to acetaldehyde and ethyl alcohol. These products were identified by NMR, but could not be quantitatively determined because of the existence of overlapping small peaks in the GC chart. The last reaction corresponds to oxidative hydrolysis of ethyl vinyl ether. Those olefins having bulky (a-methylstyrene, j8-methylstyrene, and allylbenzene) or electon-withdrawing substituents (1-bromo-l-propene, 1-chloro-l-pro-pene, fumalonitrile, acrylonitrile, and methylacrylate) are not oxidized. 

S)-(-)-CITRONELLOL from geraniol. An asymmetrically catalyzed Diels-Alder reaction is used to prepare (1 R)-1,3,4-TRIMETHYL-3-C YCLOHEXENE-1 -CARBOXALDEHYDE with an (acyloxy)borane complex derived from L-(+)-tartaric acid as the catalyst. A high-yield procedure for the rearrangement of epoxides to carbonyl compounds catalyzed by METHYLALUMINUM BIS(4-BROMO-2,6-DI-tert-BUTYLPHENOXIDE) is demonstrated with a preparation of DIPHENYL-ACETALDEHYDE from stilbene oxide. A palladium/copper catalyst system is used to prepare (Z)-2-BROMO-5-(TRIMETHYLSILYL)-2-PENTEN-4-YNOIC ACID ETHYL ESTER. The coupling of vinyl and aryl halides with acetylenes is a powerful carbon-carbon bond-forming reaction, particularly valuable for the construction of such enyne systems. 

T. Ooi, K. Maruoka, and H. Yamamoto 95 REARRANGEMENT OF trans-STILBENE OXIDE TO DIPHENYL-ACETALDEHYDE WITH CATALYTIC METHYLALUMINUM BIS(4-BROMO-2,6-DI-tert-BUTYLPHENOXIDE)... 

The Skraup-type reactions proceed by the use of acrolein or 2-bromo-acrolein in the presence of mineral acids or with glycerol and sulfuric acid [52CI(L)562 60NKZ509], The quinaldine-type products are afforded by acetaldehyde, crotonaldehyde, or paraldehyde in the presence of hydrochloric acid (54JCS286). 

In order to testify to the versatility of the Reformatsky reaction, two examples of three-component processes are presented the synthesis of 3-aryl-4,4-dimethyl-2-oxaspiro[5.5] undecane-1,5-diones 1485 (equation 12), and the coupling of two molecules of methyl 2-bromo-2-methyl propanoate (If) with an oxoaryl acetaldehyde 15 to afford 3a-aryl-3,3,6,6-tetramethyl-tetrahydrofuro[3,2-b]furan-2,5-dione 1686 (equation 13). 

The synthesis of benzo[6]thiophenes by the PPA-promoted cyclization of (arylthio)acetaldehyde dimethyl or diethyl acetals [Eq. (4)] was introduced by Tilak287, 288 in 1950 and improved in 1951.289 The acetals are readily prepared from aryl mercaptans and bromo-acetaldehyde dimethyl (or diethyl) acetal in the presence of sodium ethoxide, or by reaction of an aryllithium compound with [(MeO)2CHCH2S]2.290 Diethyl acetal as starting material sometimes gives better yields of product than the corresponding dimethyl acetal.291 Optimum yields of benzo[6]thiophenes are obtained when cyclization of the acetals is carried out under reduced pressure so that the lower boiling benzo[6]thiophenes distill as soon as they are formed. Experimental conditions for obtaining optimum yields vary from case... 

The synthesis of hydroxy- and aminoindolizines has been examined in some detail.30 The reaction of 2-(nitromethyl)pyridine and bromo-acetaldehyde gave 1-nitroindolizine, which was reduced to the corresponding amino compound [Eq. (2)]. 

Abietic ACID, 32, 1 acid sodium salt of, 32, 4 diamylamine salt of, 32, 2 Acetaldehyde, 36, 60 Acetaldehyde, diphenyl-, 38, 26 Acetal formation, from pentaerythritol and benzaldehyde, 38, 65 Acetamide, 31, 17 Acetamide, N-bromo, 31,17 a-PHENYL-, 32, 92 Acetanilide, < -benzoyl-, 37, 2 Acetanilide, -benzoyl-2-methoxy-4-nitro, 37, 4... 

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