2- Chloropropionaldehyde

Chloropropionaldehyde diethylacetal 8enzilic acid Piperidine Hydrogen chloride... 

Chloropropionaldehyde diethyl acetal Pipoxolan HCI a-Chloropropionyl chloride Carticaine... 

The oxidation of the crude /3-chloropropionaldehyde is carried out in a 200-cc. flask fitted with a cork stopper held by a clamp about 2 cm. %bove the opening of the neck. The stopper carries a mechanical stirrer, a separatory funnel, a thermometer and a glass delivery tube about 10 mm. in diameter which is connected to a water pump. The space between the stopper and the flask is closed by winding a strip of asbestos paper around it (Note 3). 

Chloropropionaldehyde is a very unstable substance which polymerizes rapidly especially in the presence of traces of hydrochloric acid. The crude material must be oxidized without delay as standing before oxidation will cause a lowering of the yield. 

Ring B of pyrimido[l,6-tf]pyrimidines has been most frequently synthesized from [3+3] atom fragments. The 6-aminopyrimidin-2-one derivative, cytidine 211, on reaction with acrylic acid under thermal conditions gave the pyrimido[l,6- ]pyrimidin-4,6-dione 212 <1996MI301> while reaction with 3-chloropropionaldehyde under base catalysis resulted in the pyrimido[l,6- ]pyrimidine-6-one 213 (Scheme 33) <1996MI501, 1996BAP209>. 

The synthesis of a triptan with a chiral side chain begins by reduction of the carboxylic acid in chiral 4-nitrophenylalanine (15-1). The two-step procedure involves conversion of the acid to its ester by the acid chloride by successive reaction with thionyl chloride and then methanol. Treatment of the ester with sodium borohy-dride then afford the alanilol (15-2). Reaction of this last intermediate with phosgene closes the ring to afford the oxazolidone (15-3) the nitro group is then reduced to the aniline (15-4). The newly obtained amine is then converted to the hydrazine (15-5). Reaction of this product with the acetal from 3-chloropropionaldehyde followed by treatment of the hydrazone with acid affords the indole (15-6). The terminal halogen on the side chain is then replaced by an amine by successive displacement by means of sodium azide followed by catalytic reduction of the azide. The newly formed amine is then methylated by reductive alkylation with formaldehyde in the presence of sodium cyanoborohydride to afford zolmitriptan (15-7) [15]. 

Problem 15.2 Give structural formulas for ( ) methyl isobutyl ketone, (b) phenylacetaldehyde, (c) 2-methyl-3-pentanone, (d) 3-hexenal, (e) /3-chloropropionaldehyde. ... 

To 340 g. (6 moles) of dry, powdered potassium hydroxide (Note 1) in a 500-cc. short-neck round-bottom flask (Note 2) is added 167 g. (1 mole) of /3-chloropropionaldehyde acetal (p. 26). The mixture is shaken vigorously and attached at once to a 3-bulb Glinsky, or other suitable column, connected to a water condenser set for distillation. The flask is heated in an oil bath at 210-2200 until nothing more distils (Note 3). The distillate is transferred to a separatory funnel and the lower aqueous layer is removed. The acrolein acetal is dried over 10 g. of potassium carbonate, filtered and distilled from a modified Claisen flask (Org. Syn. 1, 40). The yield is 98 g. (75 per cent of the theoretical, amount) of a product which boils at 122-126°. 

Acrolein acetal has always been prepared by treatment of /3-chloropropionaldehyde acetal with dry, powdered ix>tassium hydroxide.1... 

Chloropropionaldehyde acetal has been prepared by the action of acrolein on alcoholic hydrogen chloride alone,1 or in the presence of calcium chloride.2... 

In the flask is placed 64 g. of fuming nitric acid (sp. gr. 1.49) (Note 4), the stirrer is started and about one-sixth (Note 5) of the crude /3-chloropropionaldehyde is added (Note 6) very slowly through the separatory funnel. About 1 c c. of the aldehyde is added to the acid. The temperature remains constant for one or two minutes and then slowly rises. As the oxidation... 

Smith and Holm487 have reported the preparation of an unsaturated acid from an unsaturated aldehyde by use of hydrogen peroxide in the presence of selenium dioxide. 3-Chloropropionaldehyde is converted into 3-chloro-... 

Chloropropionaldehyde, 529 N-Chloro-N-sodiourethane, 115 Chlorospiro[2.4) heptadienes, 170, 171 N-Chlorosuccinimide, 115-118 N-Chlorosuccinimide-Dialkyl sulfides,... 

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