NOVELTY - Preparation (P1) of (R,S)-nicotine involves: (A) reacting 2-pyrrolidone with butanal using phosphorus pentoxide as condensing agent to obtain N-(1-butenyl)-2-pyrrolidone (a); (B) reacting the compound (a) with nicotinic acid ester in solvent using base to obtain 1-(1-butenyl)-3-nicotinoyl-pyrrolidine-2-one (b); (C) reacting the compound (b) with acid to effect decarboxylation followed a base for cyclization to obtain myosmine; and (D) hydrogenating myosmine in presence of catalyst to obtain (R,S)-nornicotine and converting (R,S)-nornicotine to (R,S)-nicotine by N-methylation.    USE - For preparation of (R,S)-nicotine, 1-(1-butenyl)-3-nicotinoyl-pyrrolidine-2-one, and myosmine (claimed). The (R,S)-nicotine is useful for synthesis of (S)-nicotine by resolution and racemization of unwanted (R)-nicotine isomer.    ADVANTAGE - The method provides improved and efficient method for forming (R,S)-nicotine; where prior art methods are expensive and are not suitable for industrial production, as enantioselective synthesis is too expensive on industrial scale. Together with the known methods for resolution and racemization of unwanted (R)-nicotine isomer, the process provides attractive and economical method for production of synthetic (S)-nicotine. The method provides alternative to natural nicotine, which has several disadvantages. The most convenient way to prepare (R,S)-nicotine is through myosmine. In prior art, myosmine was prepared by condensing N-vinylpyrrolidone with ethyl nicotinate. However preparation of N-vinylpyrrolidone involves use of acetylene gas at high temperature and pressure. The N-vinylpyrrolidone is lachrymatory and irritating to skin, lungs, and eyes. It is known to cause corneal opacity. The method finds safer alternative to this by selection of N-(1-butenyl)-2-pyrrolidone to prepare myosmine. The N-(1-butenyl)-2-pyrrolidone is stable, colorless liquid and is not lachrymatory. Its preparation, in prior art involves reacting butanal with 2-pyrrolidone in solvent using para-toluenesulfonic acid as condensing agent. Sulfonic acid and its esters are considered to be potential alkylating agents that exert genotoxic effects. Because of this, use of para-toluenesulfonic acid is avoided in industrial processes. Earlier literature describes several other catalysts such as sulfuric acid and neutral or acidic alumina for condensing aldehyde with 2-pyrrolidone. The method found that none of these catalysts gave satisfactory results. When phosphorus pentoxide is used, it is found to be excellent condensing agent and gives N-(1-butenyl)-2-pyrrolidone in good yields. Phosphorus pentoxide is soluble in water and can be removed by alkali wash during workup to give phosphate salt, which is not injurious to health on dilution. Phosphate salts are routinely used as fertilizers and in food industry. In next stage, N-(1-butenyl)-2-pyrrolidone is condensed with methyl nicotinate using sodium hydride in solvent such as tetrahydrofuran or dimethylformamide to obtain 1-(but-1-enyl)-3-nicotinoylpyrrolidin-2-one in good yields. Reaction of 1-(but-1-enyl)-3-nicotinoylpyrrolidin-2-one with strong mineral acid such as hydrochloric acid under heating results in deprotection of amide nitrogen, followed by decarboxylation to give primary amine intermediate which on treating with base results in cyclization to give myosmine. Catalytic hydrogenation of myosmine results in (R,S)-nornicotine. After workup, pure (R,S)-nornicotine can be isolated by high vacuum distillation in high yields and purity.    DETAILED DESCRIPTION - INDEPENDENT CLAIMS are included for the following:    (1) new 1-(1-butenyl)-3-nicotinoyl-pyrrolidine-2-one (b);    (2) process (P2) for preparation of compound (b); and    (3) process (P3) for preparation of myosmine involving: reacting the compound (b) with an acid (preferably hydrochloric acid), followed by a base (preferably sodium hydroxide).