Describing the process of synthesizing a particular chemical utilizing a naturally occurring chemical as a starting material, thus obviating part of a total synthesis; e.g., the conversion of cholesterol (obtained from a natural source) into a corticosteroid.
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semi·syn·thet·ic -sin-'thet-ik adj
1) produced by chemical alteration of a natural starting material <\semisynthetic penicillins>
2) containing both chemically identified and complex natural ingredients <a \semisynthetic diet>
semi·syn·thet·i·cal·ly -i-k(ə-)lē adv
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semi·syn·thet·ic (sem″e-sin-thetґik) produced by chemical manipulation of naturally occurring substances.Medical dictionary. 2011.