The following molecule is thyrotropin-releasing hormone (TRH). It is secreted by the hypothalamus, causing the release of thyrotropin from the pituitary gland, which, in turn, stimulates the thyroid gland. The thyroid produces hormones, such as thyroxine, that control metabolism in general. 

The initial isolation of TRH required the processing of 4 tons of hypothalamic tissue, from which 1 mg of the hormone was obtained. Needless to say, it is a bit more convenient to synthesize TRH in the laboratory than to extract it from natural sources. Devise a synthesis of TRH from Glu, His, and Pro. Note that pyroglutamic acid is the lactam of Glu and may be readily obtained by heating Glu to 140°C.

Transcribed Image Text:

NH CH2 O HN-CH-C-NH-CH-C-N-CH-C-NH, Pyroglutamic acid Histidine Prolinamide