Lactones tertiary amino

The validation of such hypothesis employing 111 as electrophile and furans, thiophenes, butenolides, and tertiary amino lactone equivalent as nucleophiles enabled the synthesis of all desired products with high level of stereocontrol (99% ee) (Scheme 2.32). 

The tertiary amide group (CONR2) is a widely used DMG but it usually requires further derivatisation ° to convert it to a reactive functional group however, it readily participates in intramolecular cyclisation reactions to form lactones/ Tertiary amides have also been converted to ketones through an intermediary a-amino alkoxide that plays the role of the DMG (Scheme 11.3). 

The lower members of the homologous series of 1. Alcohols 2. Aldehydes 3. Ketones 4. Acids 5. Esters 6. Phenols 7. Anhydrides 8. Amines 9. Nitriles 10. Polyhydroxy phenols 1. Polybasic acids and hydro-oxy acids. 2. Glycols, poly-hydric alcohols, polyhydroxy aldehydes and ketones (sugars) 3. Some amides, ammo acids, di-and polyamino compounds, amino alcohols 4. Sulphonic acids 5. Sulphinic acids 6. Salts 1. Acids 2. Phenols 3. Imides 4. Some primary and secondary nitro compounds oximes 5. Mercaptans and thiophenols 6. Sulphonic acids, sulphinic acids, sulphuric acids, and sul-phonamides 7. Some diketones and (3-keto esters 1. Primary amines 2. Secondary aliphatic and aryl-alkyl amines 3. Aliphatic and some aryl-alkyl tertiary amines 4. Hydrazines 1. Unsaturated hydrocarbons 2. Some poly-alkylated aromatic hydrocarbons 3. Alcohols 4. Aldehydes 5. Ketones 6. Esters 7. Anhydrides 8. Ethers and acetals 9. Lactones 10. Acyl halides 1. Saturated aliphatic hydrocarbons Cyclic paraffin hydrocarbons 3. Aromatic hydrocarbons 4. Halogen derivatives of 1, 2 and 3 5. Diaryl ethers 1. Nitro compounds (tertiary) 2. Amides and derivatives of aldehydes and ketones 3. Nitriles 4. Negatively substituted amines 5. Nitroso, azo, hy-drazo, and other intermediate reduction products of nitro com-pounds 6. Sulphones, sul-phonamides of secondary amines, sulphides, sulphates and other Sulphur compounds... 

Amino-3-cyanofurans (307) are obtained by base catalyzed condensation of the acyloins (306) with malonodinitrile, and on acid hydrolysis yield the butenolides (308) (Scheme 80) (66CB1002). Diketene and an isocyanide react to give the lactone (309) in the presence of a tertiary base (73GEP2222405). When diphenylketene is treated with bis(cycloocta-l,5-diene)nickel and pyridine, the complex Ni(py)2(Ph2C=CO)2 is formed which is converted into compound (310) by carbon monoxide (78JOM(l52)C29). 

Ransom et al. 193 cloned the gene for mandelate racemase from Pseudomonas putida in Pseudomonas aeruginosa on the basis of the inability of the latter strain to grow on D-mandelate as a sole carbon source. The amino acid sequence was deduced from the nucleotide sequence, and the predicted molecular mass of the enzyme was 38 750[193. The enzyme is composed of eight identical subunits. The crystal structure of mandelate racemase has been solved and refined at 2.5 A resolution [194. The secondary, tertiary and quaternary structures of mandelate racemase are quite similar to those of muconate lactonizing enzyme 195, 196. Mandelate racemase is composed of two major structural domains and a small C-terminal domain. The N-terminal domain has an a + P structure, and the central domain has an a/p-barrel topology. The C-terminal domain consists of an L-shaped loop. 

Reaction with Amino Alcohols and Related Compounds. Both secondary and tertiary carbamates bearing a vicinal hydroxyl group react with carboxylic acids in the presence of DEAD and TPP to afford the corresponding esters with inversion of configuration (eq 34). Reaction of N-t-butoxycarbonylserine with methanol, DEAD, and TPP gives the corresponding methyl ester in >98% yield (eq 35). Without methanol, TV-benzyloxycarbonyl- or A-f-butoxycarbonylserine reacts with the preformed adduct of DEAD and TPP to afford the P-lactone (eq 35). The W-protected serine methyl ester (37a) and threonine methyl ester (37b) react with DEAD and TPP to give the dehydrated products (38a) and (38b) (eq 36). ... 

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