Adding of compound 1 to ylidene malononitrile would yielded polyfunctionally intermediate compound 16, which is anticipated to
cyclize into 5-(2,2-dicyano-1-phenylvinyl)-2,5-dihydro-2-aminothiophene-3-carbonitrile derivatives 17a-c.
This interesting work shows that exactly the right purified solution of linear organic molecules can
cyclize under the right conditions to present activated nucleotides.
A diepoxide is also formed that will
cyclize and generate the THF-diol that we identified from corncob bedding (Mani et al.
To further enhance the antigenicity of these peptides, later work may include introducing several constraints to these peptides to increase structural rigidity, such as by adding linkers to
cyclize the linear peptides or disulfide bonds for peptide stabilization.
At 240|degrees~C the pendant vinyl groups will begin to
cyclize thermally with no peroxide, but for any temperature below, a high temperature peroxide is required.
Using amine 28 and 4-fluorobenzaldehyde shown in Scheme 10, Awuah and Capretta combined microwave conditions and acid-catalysis to condense and
cyclize the imine adduct at [C.sub.8f]-[C.sub.1] followed by dehydrogenation to produce the 2-(4-fluorophenyl) isoquinoline 29a in excellent overall yield.
[H.sub.2]S is oxidized to [H.sub.2][S.sub.n] species with a varying number of sulfur atoms until the number of sulfur atoms reaches eight, at which point the sulfur molecules
cyclize and precipitate.
The P450-dependent hydroxylation of the methoxy group yields an intermediate corresponding to the hemiacetal of formaldehyde that can
cyclize to form a methylenedioxy bridge via an ionic mechanism involving the methylene oxonium ion intermediate.
Four molecules of this porphyrin precursor
cyclize and undergo several side-chain modifications to yield the tetrapyrrole protoporphyrin.