Acetaldehyde, from MeOH

The Pd-catalyzed reductive carbonylation of methyl acetate with CO and H2 affords acetaldehyde. The net reaction is the formation of acetaldehyde from MeOH, CO, and H2P4]. Methyl formate (109) is converted into AcOH under CO pressure in the presence of Lil and Pd(OAc)2[95],... 

A novel process for selective formation of the 13-cis double bond, by condensation of the dienolate of methyl 3-methyl-2-butenoate with p-ionylidene acetaldehyde 36 (9-trans content - 80%), has been reported (Scheme 12).(50) This reaction proceeded by formation of the intermediate lactone 37, which was not isolated. Lactonization resulted in release of a methoxide ion that in turn opened the lactone to afford 13-cis-RA as the carboxylate salt. Acidic work-up, followed by recrystallization from MeOH produced 13-cis-RA in 32% yield, >99% purity (<0.1% all-ira s-RA). 

Two series of six different dimers were investigated [58], The first series was formed by acetic acid (HAc) as one component and HAc, acetaldehyde (AcH), methanol (MeOH), phenol (PhOH), ammonia (NH3) and acetamide (AcNH2) as the other one. The second series was composed of the acetate anion (Ac-) as one component in interaction with the molecules from the first set. 

Ecteinascidin 743 is a marine tetrahydroisoquinoUne alkaloid that was isolated from Ecteinascidia turbinata, a mangrove tunicate, and is now approved by the FDA as an orphan dmg under the trade name Yondelis against soft tissue sarcoma and ovarian cancer [27]. Amine 53, isocyanide 54, acetaldehyde 55, and carboxylic acid 56 were heated in MeOH at 70°C to build up the dipeptide 60 in 90% yield (Scheme 6.5). 

Acetaldehyde (264 mg, 6 mmol) and succinic semialdehyde (204 mg, 2 mmol) were dissolved In water (20 ml) and adjusted to pH 7.5. To this solution, RibA (1000 U available from Slgma-Aldrlch) was added. After stirring in the dark for 4 days under at room temperature, the reaction was quenched by addition of acetone (40 mL), then cooled to 0°C for 20 min, and centrifuged to remove the precipitated protein. After removal of the solvent under reduced pressure, the residue was purified by flash chromatography (silica, EtOAc/MeOH, 6 1 to 1 1) to give the title compound (305 mg, 80%) as a mixture of anomers (a/p 1 5). 

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