Amide, sodium reduction

Terminal alkynes are only reduced in the presence of proton donors, e.g. ammonium sulfate, because the acetylide anion does not take up further electrons. If, however, an internal C—C triple bond is to be hydrogenated without any reduction of terminal, it is advisable to add sodium amide to the alkyne solution Hrst. On catalytic hydrogenation the less hindered triple bonds are reduced first (N.A. Dobson, 1955, 1961). 

Condensation of the anion obtained on reaction of acetonitrile with sodium amide, with o-chlorobenzophenone (36), affords the hydroxynitrile, 37. Catalytic reduction leads to the corresponding amino alcohol (note that the benzhydryl alcohol is not hydrogenolyzed). Reductive alkylation with formaldehyde and hydrogen in the presence of Raney nickel gives the antitussive a-gent, chlorphedianol (39). °... 

Silver fluoborate, reaction with ethyl bromide in ether, 46, 114 Silver nitrate, complexing with phenyl-acetylene, 46, 40 Silver oxide, 46, 83 Silver thiocyanate, 45, 71 Sodium amide, in alkylation of ethyl phenylacetate w ith (2-bromo-ethyl)benzene, 47, 72 in condensation of 2,4-pentanedione and 1 bromobutane to give 2,4-nonanedione, 47, 92 Sodium 2 ammobenzenesulfinate, from reduction of 2 mtrobenzenesul-finic acid, 47, 5... 

All that remains before the final destination is reached is the introduction of the C-l3 oxygen and attachment of the side chain. A simple oxidation of compound 4 with pyridinium chlorochro-mate (PCC) provides the desired A-ring enone in 75 % yield via a regioselective allylic oxidation. Sodium borohydride reduction of the latter compound then leads to the desired 13a-hydroxy compound 2 (83% yield). Sequential treatment of 2 with sodium bis(trimethylsilyl)amide and /(-lactam 3 according to the Ojima-Holton method36 provides taxol bis(triethylsilyl ether) (86 % yield, based on 89% conversion) from which taxol (1) can be liberated, in 80 % yield, by exposure to HF pyridine in THF at room temperature. Thus the total synthesis of (-)-taxol (1) was accomplished. 

An attempt to improve the yield of the azepin-2-amine by the addition of sodium amide to the photolysate failed, as a rapid nonphotolytic reduction of the phenyl azide to aniline took place. 

An interesting example of asymmetric induction has been used for the synthesis of (—)-l from L-tryptophan. Pictet-Spengler cyclization of the corresponding amide (127) with 5-chloropentanal afforded (—)-128 as the sole product. Removal of the unwanted carboxamide function was achieved in good yield by sodium borohydride reduction of die corresponding a-amino nitrile (—)-129, resulting in (—)-l (98). 

Similarly to 8-lactone 260, y-lactone 263, prepared also from ( )-norcamphor (228), proved to be another useful intermediate for the synthesis of all four corynantheidol stereoisomers as well as of the corresponding 18,19-didehydro derivatives. Cleavage of the a-diketone monothioketal moiety in 263 and the formation of amide 265 by its reaction with tryptamine, followed by Bischler-Napieralski cyclization and sodium borohydride reduction, resulted in a mixture... 

Sodium, with l-bromo-3-chloro-cyclobutane to give bicyclo [l.l.O]butane, 51, 55 Sodium amalgam, 50, 50, 51 Sodium amide, with 2,4-pentane-dione and diphenyliodonium chloride to give l-phenyl-2, 4-pentanedione, 51, 128 Sodium azide, 50, 107 with mixed carboxylic-carbonic anhydrides, 51, 49 Sodium borohydride, reduction of erythro-3-methanesulfony-loxy-2-butyl cyclobutanecar-boxylate, 51, 12 reduction of 2-(1-phenylcyclo-pentyl)-4,4,6-trimethyl-5,6-dihydro-1,3(4H)-oxazine to 2-(1-phenylcyclopentyl)-4,4, 6-trimethyltetrahydro-l,3-oxazine, 51, 25 Sodium cyanoborohydride, used... 

Tripelennamine Tripelennamine, iV-benzyl-iV, Ai -dimethyl-iV-2-pyridylethylenediamine (16.1.6), is synthesized by reacting 2-benzylaminopyrridine (16.1.5) with 2-dimethy-laminoethylchloride in the presence of sodium amide. 2-Benzylaminopyrridine, in turn, can be easily synthesized by reduction of a Schiff base, synthesized by condensation of 2-aminopyrridine with benzaldehyde [9-11]. 

Hydrazotc acid, HN,. ply.. = 4.72, and most of its covalent compounds (including its heavy metal salts) are explosive. It is formed (1) in 90% yield by reaction of sodium amide with nitrous oxide, (2) by reaction of hydraztntum ion with nitrous acid, (3) by oxidation of hydrazimum salts, (4) by reactio n of hydt azinium hydrate with nitrogen trichloride tin benzene solution). Hvdrazoic acid forms metal azides with the corresponding hydroxides and carbonates. It reacts with HC1 to give ammonium chlonde and nitrogen, with H2SO4 to form hydrazinium acid solfate, with benzene to form aniline, and it enters into a number of oxidation-reduction reactions. 

Dihydrothieno[2,3-6][l,5]benzothiazepines (42) were synthesized from 2-(2-thienylthio)aniline (40). Compound 40 was acylated by treatment with acetic anhydride or benzoyl chloride to give N-acyl derivatives (41), which afforded compounds 42 by cyclization with phosphorus oxychloride and subsequent reduction with sodium borohydride or Zn/HCl. N-Dimethylaminopropyl derivatives 43 were prepared by reaction with di-methylaminopropyl chloride in the presence of sodium amide (Scheme 13) (67CZP124935 68CCC1846). 

Silicon, higher chlorides of, 42 Silicon tetrabromide, 38, 40 Silicon tetrachloride, 44 Silicopropane, octachloro, 44 Silicotungstic acid, 129 analysis, 131 ether complex, 131 Silver, metallic, 4 Silver chloride, reduction of, 3 Silver cyanamide, 98 Silver residues, purification of, 2 Sodium amalgam, 10 Sodium amide, 74 Sodium azide, purification of, 79 Sodium azidodithiocarbonate, 82 Sodium butoxide, 88 Sodium hypochlorite (solution), 90 Sodium iodate, 168 Sodium metaperiodate, 170 Sodium paraperiodate, chlorine method, 169 persulfate method, 170 Strontium amalgam, 11 Sulfur hexafluoride, 121 Sulfuryl chloride, 114... 

Another illustration is the chemistry developed from MSMA amides where oxidation with pyridinium dichromate (PDC) of a methylene unit, LAH or sodium borohydride reduction of an ester moiety is performed without affecting the SMA s framework.301... 

Reduction with zinc dust in glacial acetic acid yields deoxymycelia-namide, C22H28O3N2, ferric chloride negative, with infra red spectrum reminiscent of unstrained cyclic amides. Reduction with sodium and methanol in liquid ammonia gives an unsaturated hydrocarbon side chain ("mycelene ) characterized as a 2,6-dimethylocta-2,6-diene. Mycelianamide believed to consist of a cyclic bis-acylhydroxylamino nucleus substituted by the hydrocarbon side chain (12, 13). 

---