- A Sustainable, Semi-Continuous Flow Synthesis of Hydantoins
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Hydantoins are an important class of heterocycles with applications in pharmacy, agriculture, and as intermediates in organic synthesis. Traditional synthetic procedures to access hydantoins are target oriented with multiple synthetic steps and often use reagents that are not commercially available or sustainable. Herein, an efficient process is described for accessing hydantoins starting from commercially available amines using consecutive gas–liquid transformations (oxygen, carbon dioxide). This semi-continuous process produced ten benzylic/aliphatic hydantoins in good overall yields (52–84 %).
- Vukeli?, Stella,Koksch, Beate,Seeberger, Peter H.,Gilmore, Kerry
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- Total synthesis of amiclenomycin, an inhibitor of biotin biosynthesis.
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We describe the first synthesis of amiclenomycin, a natural product that has been found to inhibit biotin biosynthesis and, as a consequence, to exhibit antibiotic properties. Structure 1, with a trans relationship between the ring substituents. had previously been proposed for amiclenomycin on the basis of its 1H NMR spectrum. We have prepared the trans and cis isomers 1 and 2 by unequivocal routes and we conclude that the natural product is in fact the cis isomer 2. The properly substituted cyclohexadienyl rings were constructed first. A cycloaddition reaction between 1,2-di(phenylsulfonyl)ethylene and the N-allyloxycarbonyl diene 13, followed by reductive elimination of the phenylsulfinyl groups, gave the cis isomer 15. To obtain the trans isomer, the O-trimethylsilyl diene was used to give the cis hydroxylated Diels-Alder adduct 33, which was transformed into the corresponding trans amino derivative by means of a Mitsunobu reaction. The L-alpha-amino acid functionality was introduced by means of a Strecker reaction on the aldehydes 16 and 42, followed by enzymatic hydrolysis with immobilised pronase.
- Mann, Stephane,Carillon, Sophie,Breyne, Olivier,Marquet, Andree
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p. 439 - 450
(2007/10/03)
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