8 research outputs found
Several New [Fe]Hydrogenase Model Complexes with a Single Fe Center Ligated to an Acylmethyl(hydroxymethyl)pyridine or Acylmethyl(hydroxy)pyridine Ligand
No full textWe have developed two novel synthetic
methods, by which two types
of mononuclear Fe model complexes for the active site of [Fe]hydrogenase
are successfully synthesized. The first type of 2-acylmethyl-6-hydroxymethylpyridine-containing
complexes, [2-COCH<sub>2</sub>-6-HOCH<sub>2</sub>C<sub>5</sub>H<sub>3</sub>N]Fe(CO)<sub>2</sub>G (<b>1</b>, G = PhCO<sub>2</sub>; <b>2</b>, PhCOS; <b>3</b>, PhCS<sub>2</sub>; <b>4</b>, 2-S-6-MeC<sub>5</sub>H<sub>3</sub>N), were prepared by
a “one-pot” method involving reaction of 2-TsO-6-HOCH<sub>2</sub>C<sub>5</sub>H<sub>3</sub>N (Ts = 4-MeC<sub>6</sub>H<sub>4</sub>SO<sub>2</sub>) with Na<sub>2</sub>Fe(CO)<sub>4</sub> followed by
treatment of the resulting Fe(0) intermediate [Na(2-CH<sub>2</sub>-6-HOCH<sub>2</sub>C<sub>5</sub>H<sub>3</sub>N)Fe(CO)<sub>4</sub>] (<b>M1</b>) with (PhCO<sub>2</sub>)<sub>2</sub>, (PhCOS)<sub>2</sub>, (PhCS<sub>2</sub>)<sub>2</sub>, and (2-S-6-MeC<sub>5</sub>H<sub>3</sub>N)<sub>2</sub> in 49–72% yields, respectively.
The second type of 2-acylmethyl-6-hydroxypyridine-containing complexes,
(2-COCH<sub>2</sub>-6-HOC<sub>5</sub>H<sub>3</sub>N)Fe(CO)<sub>2</sub>(2-SCO-6-RC<sub>5</sub>H<sub>3</sub>N) (<b>9a</b>, R = MeO; <b>9b</b>, R = PhS), could be prepared via a multiple-step synthetic
method. This method involves (i) treatment of 2-ClCO-6-RC<sub>5</sub>H<sub>3</sub>N (R = MeO, PhS) with NaSH followed by acidification
with diluted HCl to give 2-HSCO-6-RC<sub>5</sub>H<sub>3</sub>N (<b>5a</b>, R = MeO; <b>5b</b>, R = PhS); (ii) further treatment
of <b>5a</b>,<b>b</b> with KOH to afford 2-KSCO-6-RC<sub>5</sub>H<sub>3</sub>N (<b>6a</b>, R = MeO; <b>6b</b>,
R = PhS); (iii) treatment of 2-TsOCH<sub>2</sub>-6-PMBOC<sub>5</sub>H<sub>3</sub>N (PMB = 4-MeOC<sub>6</sub>H<sub>4</sub>CH<sub>2</sub>) with Na<sub>2</sub>Fe(CO)<sub>4</sub> followed by treatment of
the resulting Fe(0) intermediate [Na(2-CH<sub>2</sub>-6-PMBOC<sub>5</sub>H<sub>3</sub>N)Fe(CO)<sub>4</sub>] (<b>M2</b>) with
Br<sub>2</sub> or I<sub>2</sub> to produce (2-COCH<sub>2</sub>-6-PMBOC<sub>5</sub>H<sub>3</sub>N)Fe(CO)<sub>3</sub>X (<b>7a</b>,
X = Br; <b>7b</b>, X = I); (iv) further treatment of <b>7a</b>,<b>b</b> with <b>6a</b>,<b>b</b> to yield (2-COCH<sub>2</sub>-6-PMBOC<sub>5</sub>H<sub>3</sub>N)Fe(CO)<sub>2</sub>(2-S-6-RC<sub>5</sub>H<sub>3</sub>N) (<b>8a</b>, R = MeO; <b>8b</b>, R = PhS); and (v) finally, removal of the PMB groups from <b>8a</b>,<b>b</b> under the action of deprotecting reagent
CF<sub>3</sub>CO<sub>2</sub>H/EtSH to give complexes <b>9a</b>,<b>b</b>. All compounds <b>1</b>–<b>4</b> and <b>5a</b>,<b>b</b>–<b>9a</b>,<b>b</b> with the exception of <b>7b</b> are new and have been
characterized by elemental analysis, spectroscopy, and, particularly
for <b>1</b>, <b>4</b>, and <b>7a</b>–<b>9a</b>, X-ray crystallography
Several New [Fe]Hydrogenase Model Complexes with a Single Fe Center Ligated to an Acylmethyl(hydroxymethyl)pyridine or Acylmethyl(hydroxy)pyridine Ligand
No full textWe have developed two novel synthetic
methods, by which two types
of mononuclear Fe model complexes for the active site of [Fe]hydrogenase
are successfully synthesized. The first type of 2-acylmethyl-6-hydroxymethylpyridine-containing
complexes, [2-COCH<sub>2</sub>-6-HOCH<sub>2</sub>C<sub>5</sub>H<sub>3</sub>N]Fe(CO)<sub>2</sub>G (<b>1</b>, G = PhCO<sub>2</sub>; <b>2</b>, PhCOS; <b>3</b>, PhCS<sub>2</sub>; <b>4</b>, 2-S-6-MeC<sub>5</sub>H<sub>3</sub>N), were prepared by
a “one-pot” method involving reaction of 2-TsO-6-HOCH<sub>2</sub>C<sub>5</sub>H<sub>3</sub>N (Ts = 4-MeC<sub>6</sub>H<sub>4</sub>SO<sub>2</sub>) with Na<sub>2</sub>Fe(CO)<sub>4</sub> followed by
treatment of the resulting Fe(0) intermediate [Na(2-CH<sub>2</sub>-6-HOCH<sub>2</sub>C<sub>5</sub>H<sub>3</sub>N)Fe(CO)<sub>4</sub>] (<b>M1</b>) with (PhCO<sub>2</sub>)<sub>2</sub>, (PhCOS)<sub>2</sub>, (PhCS<sub>2</sub>)<sub>2</sub>, and (2-S-6-MeC<sub>5</sub>H<sub>3</sub>N)<sub>2</sub> in 49–72% yields, respectively.
The second type of 2-acylmethyl-6-hydroxypyridine-containing complexes,
(2-COCH<sub>2</sub>-6-HOC<sub>5</sub>H<sub>3</sub>N)Fe(CO)<sub>2</sub>(2-SCO-6-RC<sub>5</sub>H<sub>3</sub>N) (<b>9a</b>, R = MeO; <b>9b</b>, R = PhS), could be prepared via a multiple-step synthetic
method. This method involves (i) treatment of 2-ClCO-6-RC<sub>5</sub>H<sub>3</sub>N (R = MeO, PhS) with NaSH followed by acidification
with diluted HCl to give 2-HSCO-6-RC<sub>5</sub>H<sub>3</sub>N (<b>5a</b>, R = MeO; <b>5b</b>, R = PhS); (ii) further treatment
of <b>5a</b>,<b>b</b> with KOH to afford 2-KSCO-6-RC<sub>5</sub>H<sub>3</sub>N (<b>6a</b>, R = MeO; <b>6b</b>,
R = PhS); (iii) treatment of 2-TsOCH<sub>2</sub>-6-PMBOC<sub>5</sub>H<sub>3</sub>N (PMB = 4-MeOC<sub>6</sub>H<sub>4</sub>CH<sub>2</sub>) with Na<sub>2</sub>Fe(CO)<sub>4</sub> followed by treatment of
the resulting Fe(0) intermediate [Na(2-CH<sub>2</sub>-6-PMBOC<sub>5</sub>H<sub>3</sub>N)Fe(CO)<sub>4</sub>] (<b>M2</b>) with
Br<sub>2</sub> or I<sub>2</sub> to produce (2-COCH<sub>2</sub>-6-PMBOC<sub>5</sub>H<sub>3</sub>N)Fe(CO)<sub>3</sub>X (<b>7a</b>,
X = Br; <b>7b</b>, X = I); (iv) further treatment of <b>7a</b>,<b>b</b> with <b>6a</b>,<b>b</b> to yield (2-COCH<sub>2</sub>-6-PMBOC<sub>5</sub>H<sub>3</sub>N)Fe(CO)<sub>2</sub>(2-S-6-RC<sub>5</sub>H<sub>3</sub>N) (<b>8a</b>, R = MeO; <b>8b</b>, R = PhS); and (v) finally, removal of the PMB groups from <b>8a</b>,<b>b</b> under the action of deprotecting reagent
CF<sub>3</sub>CO<sub>2</sub>H/EtSH to give complexes <b>9a</b>,<b>b</b>. All compounds <b>1</b>–<b>4</b> and <b>5a</b>,<b>b</b>–<b>9a</b>,<b>b</b> with the exception of <b>7b</b> are new and have been
characterized by elemental analysis, spectroscopy, and, particularly
for <b>1</b>, <b>4</b>, and <b>7a</b>–<b>9a</b>, X-ray crystallography
Synthetic and Structural Studies of 2‑Acylmethyl-6-R-Difunctionalized Pyridine Ligand-Containing Iron Complexes Related to [Fe]-Hydrogenase
No full textAs active site models of [Fe]-hydrogenase,
tridentate 2-acylmethyl-6-methoxymethoxy-difunctionalized pyridine-containing
complexes η<sup>3</sup>-(2-COCH<sub>2</sub>-6-MeOCH<sub>2</sub>OC<sub>5</sub>H<sub>3</sub>N)Fe(CO)<sub>2</sub>(L<sub>1</sub>) (<b>4</b>, L<sub>1</sub> = I; <b>5</b>, SCN; <b>6</b>,
PhCS<sub>2</sub>) were prepared via the following multistep reactions:
(i) etherification of 2-MeO<sub>2</sub>C-6-HOC<sub>5</sub>H<sub>3</sub>N with ClCH<sub>2</sub>OMe to give 2-MeO<sub>2</sub>C-6-MeOCH<sub>2</sub>OC<sub>5</sub>H<sub>3</sub>N (<b>1</b>), (ii) reduction
of <b>1</b> with NaBH<sub>4</sub> to give 2-HOCH<sub>2</sub>-6-MeOCH<sub>2</sub>OC<sub>5</sub>H<sub>3</sub>N (<b>2</b>),
(iii) esterification of <b>2</b> with 4-toluenesulfonyl chloride
to give 2-TsOCH<sub>2</sub>-6-MeOCH<sub>2</sub>OC<sub>5</sub>H<sub>3</sub>N (<b>3</b>), (iv) nucleophilic substitution of <b>3</b> with Na<sub>2</sub>Fe(CO)<sub>4</sub> followed by treatment
of the resulting Fe(0) intermediate Na[(2-CH<sub>2</sub>-6-MeOCH<sub>2</sub>OC<sub>5</sub>H<sub>3</sub>N)Fe(CO)<sub>4</sub>] (<b>M</b><sub><b>1</b></sub>) with I<sub>2</sub> to give complex <b>4</b>, and (v) condensation of <b>4</b> with KSCN and PhCS<sub>2</sub>K to give complexes <b>5</b> and <b>6</b>, respectively.
In contrast to the preparation of complexes <b>4</b>–<b>6</b>, bidentate 2-acylmethyl-6-methoxymethoxy-difunctionalized
pyridine-containing model complexes η<sup>2</sup>-(2-COCH<sub>2</sub>-6-MeOCH<sub>2</sub>OC<sub>5</sub>H<sub>3</sub>N)Fe(CO)<sub>2</sub>(I)(L<sub>2</sub>) (<b>7</b>, L<sub>2</sub> = PPh<sub>3</sub>; <b>8</b>, Cy-C<sub>6</sub>H<sub>11</sub>NC) and η<sup>2</sup>-(2-COCH<sub>2</sub>-6-MeOCH<sub>2</sub>OC<sub>5</sub>H<sub>3</sub>N)Fe(CO)<sub>2</sub>(L<sub>3</sub>) (<b>9</b>, L<sub>3</sub> = 2-SC<sub>5</sub>H<sub>4</sub>N; <b>10</b>, 8-SC<sub>9</sub>H<sub>6</sub>N) were prepared by ligand exchange reactions
of <b>4</b> with PPh<sub>3</sub>, Cy-C<sub>6</sub>H<sub>11</sub>NC, 2-KSC<sub>5</sub>H<sub>4</sub>N, and 8-KSC<sub>9</sub>H<sub>6</sub>N, respectively. Particularly interesting is that the tridentate
2,6-bis(acylmethyl)pyridine- and 2-acylmethyl-6-arylthiomethylpyridine-containing
model complexes η<sup>3</sup>-[2,6-(COCH<sub>2</sub>)<sub>2</sub>C<sub>5</sub>H<sub>3</sub>N]Fe(CO)<sub>2</sub>(L<sub>4</sub>) (<b>11</b>, L<sub>4</sub> = PPh<sub>3</sub>; <b>12</b>, CO)
and η<sup>3</sup>-2-(COCH<sub>2</sub>-6-ArSCH<sub>2</sub>C<sub>5</sub>H<sub>3</sub>N)Fe(CO)<sub>2</sub>(ArS) (<b>13</b>, ArS
= PhS; <b>14</b>, 2-S-5-MeC<sub>4</sub>H<sub>2</sub>O) were
obtained, unexpectedly, when 2,6-(TsOCH<sub>2</sub>)<sub>2</sub>C<sub>5</sub>H<sub>3</sub>N reacted with Na<sub>2</sub>Fe(CO)<sub>4</sub> followed by treatment of the resulting mixture with ligands PPh<sub>3</sub> and CO or disulfides (PhS)<sub>2</sub> and (2-S-5-MeC<sub>4</sub>H<sub>2</sub>O)<sub>2</sub>. Reactions of ligand precursors <b>3</b> and 2,6-(TsOCH<sub>2</sub>)<sub>2</sub>C<sub>5</sub>H<sub>3</sub>N with Na<sub>2</sub>Fe(CO)<sub>4</sub> were monitored by
in situ IR spectroscopy, and the possible pathways for producing complexes <b>4</b> and <b>11</b>–<b>14</b> via intermediates
Na[(2-CH<sub>2</sub>-6-MeOCH<sub>2</sub>OC<sub>5</sub>H<sub>3</sub>N)Fe(CO)<sub>4</sub>] (<b>M</b><sub><b>1</b></sub>),
Na[(2-CH<sub>2</sub>-6-TsOCH<sub>2</sub>C<sub>5</sub>H<sub>3</sub>N)Fe(CO)<sub>4</sub>] (<b>M</b><sub><b>2</b></sub>),
and (2-COCH<sub>2</sub>-6-CH<sub>2</sub>C<sub>5</sub>H<sub>3</sub>N)Fe(CO)<sub>3</sub> (<b>M</b><sub><b>3</b></sub>) are
suggested. New compounds <b>1</b>–<b>14</b> were
characterized by elemental analysis, spectroscopy, and, for some of
them, X-ray crystallography
A Novel Acylmethylpyridinol Ligand Containing Dinuclear Iron Complex Closely Related to [Fe]-Hydrogenase
No full textOn synthesizing the PMB-protected
mononuclear iron complexes [2-C(O)CH<sub>2</sub>-6-PMBOC<sub>5</sub>H<sub>3</sub>N]Fe(CO)<sub>3</sub>I (<b>6</b>) and [2-C(O)CH<sub>2</sub>-6-PMBOC<sub>5</sub>H<sub>3</sub>N]Fe(CO)<sub>2</sub>(2-SC<sub>5</sub>H<sub>4</sub>N) (<b>7</b>), the novel acylmethylpyridinol
ligand containing dinuclear iron
complex [2-C(O)CH<sub>2</sub>-6-HOC<sub>5</sub>H<sub>3</sub>N]Fe<sub>2</sub>(CO)<sub>4</sub>[2′-C(O)CH<sub>2</sub>-6′-OC<sub>5</sub>H<sub>3</sub>N](2-SC<sub>5</sub>H<sub>4</sub>N) (<b>9</b>), which is closely related to the active site of [Fe]-hydrogenase,
has been prepared unexpectedly via removal of the PMB protecting group
from <b>7</b> under the action of excess trifluoroacetic acid.
The [Fe]-hydrogenase-related complex <b>9</b> and its precursor
complexes <b>6</b> and <b>7</b> have been fully characterized
by elemental analysis, spectroscopy, and X-ray crystallography
Synthetic and Structural Studies of 2‑Acylmethyl-6-R-Difunctionalized Pyridine Ligand-Containing Iron Complexes Related to [Fe]-Hydrogenase
No full textAs active site models of [Fe]-hydrogenase,
tridentate 2-acylmethyl-6-methoxymethoxy-difunctionalized pyridine-containing
complexes η<sup>3</sup>-(2-COCH<sub>2</sub>-6-MeOCH<sub>2</sub>OC<sub>5</sub>H<sub>3</sub>N)Fe(CO)<sub>2</sub>(L<sub>1</sub>) (<b>4</b>, L<sub>1</sub> = I; <b>5</b>, SCN; <b>6</b>,
PhCS<sub>2</sub>) were prepared via the following multistep reactions:
(i) etherification of 2-MeO<sub>2</sub>C-6-HOC<sub>5</sub>H<sub>3</sub>N with ClCH<sub>2</sub>OMe to give 2-MeO<sub>2</sub>C-6-MeOCH<sub>2</sub>OC<sub>5</sub>H<sub>3</sub>N (<b>1</b>), (ii) reduction
of <b>1</b> with NaBH<sub>4</sub> to give 2-HOCH<sub>2</sub>-6-MeOCH<sub>2</sub>OC<sub>5</sub>H<sub>3</sub>N (<b>2</b>),
(iii) esterification of <b>2</b> with 4-toluenesulfonyl chloride
to give 2-TsOCH<sub>2</sub>-6-MeOCH<sub>2</sub>OC<sub>5</sub>H<sub>3</sub>N (<b>3</b>), (iv) nucleophilic substitution of <b>3</b> with Na<sub>2</sub>Fe(CO)<sub>4</sub> followed by treatment
of the resulting Fe(0) intermediate Na[(2-CH<sub>2</sub>-6-MeOCH<sub>2</sub>OC<sub>5</sub>H<sub>3</sub>N)Fe(CO)<sub>4</sub>] (<b>M</b><sub><b>1</b></sub>) with I<sub>2</sub> to give complex <b>4</b>, and (v) condensation of <b>4</b> with KSCN and PhCS<sub>2</sub>K to give complexes <b>5</b> and <b>6</b>, respectively.
In contrast to the preparation of complexes <b>4</b>–<b>6</b>, bidentate 2-acylmethyl-6-methoxymethoxy-difunctionalized
pyridine-containing model complexes η<sup>2</sup>-(2-COCH<sub>2</sub>-6-MeOCH<sub>2</sub>OC<sub>5</sub>H<sub>3</sub>N)Fe(CO)<sub>2</sub>(I)(L<sub>2</sub>) (<b>7</b>, L<sub>2</sub> = PPh<sub>3</sub>; <b>8</b>, Cy-C<sub>6</sub>H<sub>11</sub>NC) and η<sup>2</sup>-(2-COCH<sub>2</sub>-6-MeOCH<sub>2</sub>OC<sub>5</sub>H<sub>3</sub>N)Fe(CO)<sub>2</sub>(L<sub>3</sub>) (<b>9</b>, L<sub>3</sub> = 2-SC<sub>5</sub>H<sub>4</sub>N; <b>10</b>, 8-SC<sub>9</sub>H<sub>6</sub>N) were prepared by ligand exchange reactions
of <b>4</b> with PPh<sub>3</sub>, Cy-C<sub>6</sub>H<sub>11</sub>NC, 2-KSC<sub>5</sub>H<sub>4</sub>N, and 8-KSC<sub>9</sub>H<sub>6</sub>N, respectively. Particularly interesting is that the tridentate
2,6-bis(acylmethyl)pyridine- and 2-acylmethyl-6-arylthiomethylpyridine-containing
model complexes η<sup>3</sup>-[2,6-(COCH<sub>2</sub>)<sub>2</sub>C<sub>5</sub>H<sub>3</sub>N]Fe(CO)<sub>2</sub>(L<sub>4</sub>) (<b>11</b>, L<sub>4</sub> = PPh<sub>3</sub>; <b>12</b>, CO)
and η<sup>3</sup>-2-(COCH<sub>2</sub>-6-ArSCH<sub>2</sub>C<sub>5</sub>H<sub>3</sub>N)Fe(CO)<sub>2</sub>(ArS) (<b>13</b>, ArS
= PhS; <b>14</b>, 2-S-5-MeC<sub>4</sub>H<sub>2</sub>O) were
obtained, unexpectedly, when 2,6-(TsOCH<sub>2</sub>)<sub>2</sub>C<sub>5</sub>H<sub>3</sub>N reacted with Na<sub>2</sub>Fe(CO)<sub>4</sub> followed by treatment of the resulting mixture with ligands PPh<sub>3</sub> and CO or disulfides (PhS)<sub>2</sub> and (2-S-5-MeC<sub>4</sub>H<sub>2</sub>O)<sub>2</sub>. Reactions of ligand precursors <b>3</b> and 2,6-(TsOCH<sub>2</sub>)<sub>2</sub>C<sub>5</sub>H<sub>3</sub>N with Na<sub>2</sub>Fe(CO)<sub>4</sub> were monitored by
in situ IR spectroscopy, and the possible pathways for producing complexes <b>4</b> and <b>11</b>–<b>14</b> via intermediates
Na[(2-CH<sub>2</sub>-6-MeOCH<sub>2</sub>OC<sub>5</sub>H<sub>3</sub>N)Fe(CO)<sub>4</sub>] (<b>M</b><sub><b>1</b></sub>),
Na[(2-CH<sub>2</sub>-6-TsOCH<sub>2</sub>C<sub>5</sub>H<sub>3</sub>N)Fe(CO)<sub>4</sub>] (<b>M</b><sub><b>2</b></sub>),
and (2-COCH<sub>2</sub>-6-CH<sub>2</sub>C<sub>5</sub>H<sub>3</sub>N)Fe(CO)<sub>3</sub> (<b>M</b><sub><b>3</b></sub>) are
suggested. New compounds <b>1</b>–<b>14</b> were
characterized by elemental analysis, spectroscopy, and, for some of
them, X-ray crystallography
A Novel Acylmethylpyridinol Ligand Containing Dinuclear Iron Complex Closely Related to [Fe]-Hydrogenase
No full textOn synthesizing the PMB-protected
mononuclear iron complexes [2-C(O)CH<sub>2</sub>-6-PMBOC<sub>5</sub>H<sub>3</sub>N]Fe(CO)<sub>3</sub>I (<b>6</b>) and [2-C(O)CH<sub>2</sub>-6-PMBOC<sub>5</sub>H<sub>3</sub>N]Fe(CO)<sub>2</sub>(2-SC<sub>5</sub>H<sub>4</sub>N) (<b>7</b>), the novel acylmethylpyridinol
ligand containing dinuclear iron
complex [2-C(O)CH<sub>2</sub>-6-HOC<sub>5</sub>H<sub>3</sub>N]Fe<sub>2</sub>(CO)<sub>4</sub>[2′-C(O)CH<sub>2</sub>-6′-OC<sub>5</sub>H<sub>3</sub>N](2-SC<sub>5</sub>H<sub>4</sub>N) (<b>9</b>), which is closely related to the active site of [Fe]-hydrogenase,
has been prepared unexpectedly via removal of the PMB protecting group
from <b>7</b> under the action of excess trifluoroacetic acid.
The [Fe]-hydrogenase-related complex <b>9</b> and its precursor
complexes <b>6</b> and <b>7</b> have been fully characterized
by elemental analysis, spectroscopy, and X-ray crystallography
Additional file 1: of FOXP3 Is a HCC suppressor gene and Acts through regulating the TGF-β/Smad2/3 signaling pathway
No full textSupplementary Methods. (DOC 37 kb
Additional file 2: of FOXP3 Is a HCC suppressor gene and Acts through regulating the TGF-β/Smad2/3 signaling pathway
No full textThe additional file contains 6 sub-files. (ZIP 2185 kb
