Synthesis of diaryl selenides using the in situ reagent SeCl2

Article abstract of DOI:10.1016/j.tetlet.2004.11.125

Reactions of in situ prepared SeCl₂ with Grignard reagents (prepared from bromobenzene, o-tolyl bromide, 2,6-dimethyl-4-tert-butyl-1- bromobenzene, and 1-bromo-2-methylnaphthalene) and dilithiated benzamides (prepared from N-phenyl, N-cyclohexyl, and N-isopropyl benzamide) are described.

Full text of DOI:10.1016/j.tetlet.2004.11.125

Tetrahedron
Letters
Tetrahedron Letters 46 (2005) 665–669
Synthesis of diaryl selenides using the in situ reagent SeCl2
a
Sanjio S. Zade, Snigdha Panda, Harkesh B. Singh and Gotthelf Wolmersh a¨ user
a
a,
b,
*
a
Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai 400 076, India
b
Fachbereich Chemie, Universit a¨ t Kaiserslautern, Postfach 3049, Kaiserslautern 67653, Germany
Received 14 September 2004; revised 19 November 2004; accepted 25 November 2004
Available online 10 December 2004
Abstract—Reactions of in situ prepared SeCl with Grignard reagents (prepared from bromobenzene, o-tolyl bromide, 2,6-dimethyl-
2
4
-tert-butyl-1-bromobenzene, and 1-bromo-2-methylnaphthalene) and dilithiated benzamides (prepared from N-phenyl, N-cyclo-
hexyl, and N-isopropyl benzamide) are described.
Ó 2004 Elsevier Ltd. All rights reserved.
The preparation of divalent selenium compounds has
attracted considerable efforts due to the fact that these
compounds have widespread applications. Diarylsele-
nides with amino and amide groups, ebselen (2-phenyl-
route, dialkyl selenides can be obtained in excellent
yield. However, this route is not suitable for unactivated
or electron rich aryl halides as these reactions require
elevated temperature (130–170 °C) with highly polar sol-
vents (like HMPA, DMF, and NMP) and long reaction
times (>24 h), and the reaction yields are unsatisfactory
1
1
,2-benzisoselenazol-3(2H)-one) and its analogues, and
selenium analogues of 2,3-dihydrobenzofuranol with
2
9
Se(II) instead of oxygen are useful antioxidants. The
ligand chemistry of divalent selenium compounds is a
(<30%). The alternative approach for the preparation
of diaryl selenides and other Se(II) systems involves an
3
2+
well-developed branch of selenium chemistry. Several
chiral diorganoselenides have been utilized as ligands
electrophilic Se
dithiocarbamate [Se(dtc)2]. However, the synthesis of
source such as selenium diethyl-
0
1
4
in chiral catalysis.
Se(dtc) is a multi-step process and requires the expen-
2
1
1
sive precursor selenium dioxide.
The synthesis of diorganoselenides has been approached
by various routes, which include; (i) the reaction of sele-
nium dianions with aryl/alkyl halides, (ii) the reaction of
aryl/alkyl metal selenolates with alkyl/aryl halides, (iii)
the reaction of organometallic species (e.g., Grignard
reagents, organolithiums) with selenium dications, (iv)
In view of the above we considered the use of SeCl as a
2
2
+
source of Se for preparing diaryl selenide and related
systems, in particular, ebselen. The synthesis of SeCl2
in pure and stable form has always been difficult. Whilst
a number of attempts have been made to prepare pure
SeCl /SeBr . In the preparation of the [1,4,2,3]-diselena-
1
reduction of diselenides by metals to monoselenides.
The selenium dianion can be produced easily by the
2
2
dizolyl radical and its dimer, SeCl was synthesized in
2
5
12
treatment of elemental selenium with superhydride,
6
situ by the disproportionation of SeCl and Se. Milne
4
7
sodium borohydride, sodium hydride or directly by
treating selenium with alkali metals in various solvents
in the presence or absence of an electron carrier. Sub-
sequent reaction of the selenium dianion with the alkyl/
aryl halide affords the diorganoselenide. Using this
has synthesized SeCl /SeBr in acetonitrile and studied
2
2
1
3
their stability and composition in different solvents.
Bryce and Chesney reported PhSO SeCl as a synthetic
8
9
2
equivalent for SeCl for the formation of C–Se and N–
2
1
4
Se bonds. Recently, Chivers and co-workers developed
a novel reaction to prepare SeCl in THF using Se pow-
2
1
5
der and sulfuryl chloride as synthons. The stability
of SeCl in various solvents has been investigated by
2
Keywords: Selenium dichloride; 2-Phenyl-1,2-benzisoselenazol-3(2H)-
one; Lithiation; Diorganoselenide; Benzamide.
77
Se NMR. The prepared SeCl was further character-
2
ized by Raman spectroscopy and by X-ray structures
of its adducts with tetrahydrothiophene and tetra-
methylthiourea. The authors extended their studies by
reacting SeCl2 with bis(trimethylsilylamino)sulfane to
*
Corresponding author. Tel.: +91 22 2576 7190; fax: +91 22 2572
480; e-mail addresses: chhbsia@chem.iitb.ac.in; wolmersh@chemie.
unk-kl.de
3
Fax: +49 631 205 2187.
0
040-4039/$ - see front matter Ó 2004 Elsevier Ltd. All rights reserved.
doi:10.1016/j.tetlet.2004.11.125

6
66
S. S. Zade et al. / Tetrahedron Letters 46 (2005) 665–669
1,23
2
obtain cyclic compounds, which mimic the structures of
1
nide 10, respectively, in an 11:1 ratio. The
formation of the diselenide may be due to oxidation of
6
(SN)x polymers. They also studied the reaction of
SeCl with t-butylamine producing different interesting
acyclic and cyclic compounds having selenium and
2
2
þ
2+
some Se to Se in addition to Se .
2
1
7
nitrogen backbones. However, the application of
SeCl2 for the preparation of organoselenium com-
pounds has not been demonstrated. In this report, we
have investigated the utility of SeCl as a dicationic
2
Se source for the preparation of several organosele-
nium compounds.
Heteroatom directed aromatic lithiation is a key step in
the synthesis of various heterocyclic ring systems and
naturally occurring compounds. Recently, this strat-
egy has been found to be a promising approach for
25
the synthesis of various organoselenium compounds.
2
4
2
+
The dilithiated species 15–17 were produced by treat-
ment of benzamides 12–14 with 2 equivof n-BuLi at
0 °C. Interestingly, in the reaction of dilithiated benzani-
Selenium dichloride was conveniently generated in situ
by the treatment of elemental selenium with SO Cl in
lide with SeCl , only a cyclization reaction was observed
2
2
2
1
5
26
THF. The reaction yields a clear brownish red solu-
tion, which was used for further reactions. The Grignard
reagents 1 and 2 were prepared by stirring a THF solu-
tion of bromobenzene and o-tolyl bromide with Mg
turnings for 6 and 4 h, respectively. On addition of the
affording ebselen 18 in 40% yield (Eq. 1, Scheme 4).
Although ebselen is a major GPx mimic, its synthesis
2
7
has been a challenge ever since it was first prepared
8
2
in 1924. In the earliest and most direct approach,
0
2,2 -diselenobis(benzoic acid) was converted to a selenen-
yl chloride benzoyl chloride, which was treated with
SeCl solution at ꢀ78 °C, the turbid solutions changed
2
2
7c
to orange after which the reaction mixtures were
allowed to warm to the room temperature. After usual
aniline to give ebselen.
The most expedient method
2
7d
was reported by Engman and Hallberg et al. and uti-
lized a one-pot procedure in which benzanilide was
ortho-lithiated and treated with selenium powder, fol-
lowed by cuprous bromide-mediated oxidative ring clo-
sure. A free radical synthesis of ebselen has been
achieved by intramolecular homolytic substitution with
1
8
work-up and purification, the monoselenides 3 and 4
were obtained as yellow oil and a colorless solid in good
yields (Scheme 1).
1
9
2
0
21
The Grignard reagents 5 and 8 were prepared by re-
ported methods. A similar procedure to that described
2
7e,f
amidyl radicals.
with dilithium salt 16 afforded monoselenide 19 in mod-
In contrast, the reaction of SeCl2
2
2
above was followed to obtain the monoselenide 6
2
3
29
(
Scheme 2) and 9 (Scheme 3).
erate yield (Eq. 2, Scheme 3). However, the treatment
of SeCl with dilithium salt 17 afforded only a black,
2
Interestingly, during crystallization of the crude product
, both yellow and red crystals were obtained, which
sticky material, which decomposed to give an insoluble
material on passing through a silica gel column.
9
were separated manually. Characterization of these
two different colored compounds revealed that the yel-
low and red crystals were monoselenide 9 and disele-
Organoselenenyl chlorides have potential applications in
organic synthesis to manipulate unactivated carbon–
2
3
THF
Se + SO Cl2
SeCl2 + SO2
2
R
R
R
0
.5 equiv. SeCl2
THF
Mg, THF
Br
MgBr
) Se
2
1
2
R = H
R = Me
3 R = H
4 R = Me
Scheme 1.
0
.5 equiv. SeCl2,
THF
Mg, THF
Br
MgBr
)
Se
2
1
equiv.
5
6
SeCl2
SeCl
7
Scheme 2.

S. S. Zade et al. / Tetrahedron Letters 46 (2005) 665–669
667
0
.5 equiv. SeCl2,
THF
Mg, THF
yellow
Br
MgBr
) Se
2
9
+
8
1
equiv.
SeCl2
red
Se )
2
10
SeCl
1
1
Scheme 3.
O
O
O
2
equiv. n-BuLi
NHPh
NPh 0.5 equiv. SeCl
Li
2
N
Se
Ph eq. 1
THF, 0 ºC → rt
Li
5
78 ºC rt
→
-
1
2
1
1
8
O
O
O
2
equiv. n-BuLi
Nc-Hex SeCl , THF
2
NHc-Hex
NHc-Hex
Se
THF, 0 ºC → rt
Li
-78 ºC → rt
Li
eq. 2
2
1
3
1
6
1
9
O
O
O
2
equiv. n-BuLi
NPri
Li
SeCl , THF
2
NHPri
Pri
N
Se
THF, 0 ºC → rt
-78 ºC
→
rt
Li
eq. 3
1
4
1
7
20
or
O
Black, sticky
material
NHPri
Se
2
2
1
Scheme 4.
carbon double bonds as well as to prepare organosele-
peri interaction. Compound 9 was additionally charac-
31
terized by single crystal X-ray crystallography.
3
0
nium compounds. In this regard, the synthesis of
arylselenenyl halides 7 and 11 was attempted. However,
all attempts to prepare the aryl selenenyl chlorides by
treatment of Grignard reagents/lithiated intermediates
with 1 equivof SeCl 2 were unsuccessful, in all cases
the disubstituted products were obtained (Schemes 2
and 3).
In summary, the treatment of SeCl2 with Grignard
reagents (1:2) prepared from bromobenzene, o-tolyl
bromide, 2,6-dimethyl-5-t-butyl-1-bromobenzene, and
1-bromo-2-methylnaphthalene afforded the correspond-
ing monoselenides in very good yields. However, the 1:1
reactions did not afford the expected selenenyl halides.
The newly-synthesized compounds were characterized
The reaction of SeCl with dilithiated benzanilide affor-
2
1
77
by H, Se NMR and mass spectroscopy, and elemental
analysis. In the case of 9, the signal for the C-8 proton
was shifted considerably downfield compared to the
other aromatic protons. This is probably due to a 1,8-
ded the cyclized product, ebselen in moderate yield. Fur-
thermore, N-alkyl analogues of benzanilide did not
afforded cyclized products, but gave the corresponding
monoselenides instead.

668
S. S. Zade et al. / Tetrahedron Letters 46 (2005) 665–669
T.; Palstra, T. T. M.; Scott, S. R. J. Chem. Soc., Chem.
Acknowledgements
Commun. 1992, 1265–1266; (b) Cordes, A. W.; Bryan, C.
D.; Davis, W. M.; de Laat, R. H. S.; Glarum, H.;
Goddard, J. D.; Haddon, R. C.; Hicks, R. G.; Kennepohl,
D. K. J. Am. Chem. Soc. 1993, 115, 7232–7239.
We are grateful to the Department of Science and Tech-
nology (DST), New Delhi for funding this work. Addi-
tional help from the Regional Sophisticated
Instrumentation Center (RSIC), Indian Institute of
Technology (IIT), Bombay, for 300 MHz NMR spec-
troscopy is gratefully acknowledged. S.S.Z. wishes to
thank CSIR, New Delhi, for a fellowship.
1
1
1
3. Milne, J. Polyhedron 1985, 4, 65–68.
4. Bryce, M. R.; Chesney, A. Chem. Commun. 1995, 195–196.
5. Maaninen, A.; Chivers, T.; Parvez, M.; Pietik a¨ inen, J.;
Laitinen, R. S. Inorg. Chem. 1999, 4093–4097.
16. Konu, J.; Maaninen, A.; Paananen, K.; Ingman, P.;
Laitinen, R. S.; Chivers, T.; Valkonen, J. Inorg. Chem.
2
002, 41, 1430–1435.
1
7. (a) Maaninen, T.; Chivers, T.; Laitinen, R. S.; Schatte, G.;
Nissinen, M. Inorg. Chem. 2000, 39, 5341–5347; (b)
Maaninen, T.; Chivers, T.; Laitinen, R. S.; Wegelius, E.
Chem. Commun. 2000, 759–760.
Supplementary data
Supplementary data associated with this article can be
found, in the online version, at doi:10.1016/j.tetlet.
1
2
8. Typical procedure: SeCl , prepared separately in a three-
2
004.11.125.
necked flask, was added via cannula to the solution of
Grignard reagent at ꢀ78 °C in a dropwise manner. The
mixture was allowed to warm to rt. The resulting solution
was poured into water and extracted with dichlorome-
thane. The organic layer was filtered through Celite, and
dried (Na SO ). Evaporation of the solvent afforded a
References and notes
. (a) Paulmier, C. Selenium Reagents and Intermediates in
1
2
4
Organic Synthesis; Pergamon: Oxford, 1985; (b) Chemistry
of Organoselenium and Tellurium Compounds; Patai, S.,
Rappoport, Z., Eds.; John Wiley & Sons: New York,
gray-colored solid, which was purified by passing through
a silica gel column (petroleum ether, 60–80) and recrys-
tallized from petroleum ether (60–80) to give colorless
1
987; (c) Organoselenium Chemistry:
A
Practical
crystals of the desired compound.
1
Approach; Back, T. G., Ed.; Oxford University Press:
Oxford, 1999; (d) Topics in Current Chemistry; Wirth, T.,
Ed.; Springer: Heidelberg, 2000; Vol. 208.
19. Yields: 3: 82% and 4: 74%. The mp of 4 and H NMR data
for 3 and 4 match with reported values Taniguchi, M.;
Onami, T. J. Org. Chem. 2004, 69, 915–920.
2
. (a) Engman, L.; Stern, D.; Pelcmanl, M.; Andersson,
C.-M. J. Org. Chem. 1994, 59, 1973–1979; (b) Andersson,
C.-M.; Hallberg, A.; Hoegberg, T. Adv. Drug Res. 1996,
20. Mugesh, G.; Panda, A.; Singh, H. B.; Punekar, N. S.;
Butcher, R. J. J. Am. Chem. Soc. 2001, 123, 839–850.
21. Mugesh, G.; Panda, A.; Kumar, S.; Apte, S. D.; Singh, H.
B.; Butcher, R. J. Organometallics 2002, 21, 884–892.
28, 65–180; (c) Malmstrom, J.; Jonsson, M.; Cotgreave, I.
1
A.; Hammarstrom, L.; Sjodin, M.; Engman, L. J. Am.
Chem. Soc. 2001, 123, 3434–3440; (d) Mugesh, G.; Singh,
H. B. Chem. Soc. Rev. 2000, 29, 347–357; (e) Mugesh, G.;
du Mont, W.-W.; Sies, H. Chem. Rev. 2001, 101, 2125–
22. Compound 6: yield: 1.5 g (75%). Mp 97 °C. H NMR
(300 MHz, CDCl ): d 1.26 (s, 18H), 2.28 (s, 12H), 7.01 (s,
3
1
3
4H). C NMR (400 MHz, CDCl ): d 24.02, 31.37, 34.29,
3
7
7
125.25, 129.64, 141.08, 150.27. Se NMR (300 MHz,
+
2179.
CDCl ): d 231. GC–MS: m/z (%) 402 (M , 55), 387 (50),
3
3
4
. (a) Gysling, H. J. Coord. Chem. Rev. 1982, 42, 133–244; (b)
Hope, E. G.; Levason, W. Coord. Chem. Rev. 1993, 122,
109–170; (c) Levason, W.; Orchard, S. D.; Reid, G. Coord.
Chem. Rev. 2002, 225, 159–199.
. Hiroi, K. In Organopalladium Chemistry for Organic
Synthesis; Negishi, E.-I., de Meijere, A., Eds.; 2000; Vol.
1
242 (12), 225 (62), 186 (37), 158 (25), 145 (35), 131 (55),
119 (54), 105 (51), 91 (52), 77 (9), 57 (100). Anal. Calcd for
C H Se: C, 71.85; H, 8.53. Found: C, 71.63; H, 9.07.
2
4
34
1
23. Yellow compound 9: yield: 1.5 g (80%). Mp 108 °C. H
NMR (300 MHz, CDCl ): d 2.36 (s, 6H), 7.24 (d,
3
J = 8.4 Hz, 2H), 7.36–7.46 (m, 4H), 7.68 (d, J = 8.4 Hz,
2H), 7.74–7.80 (m, 2H), 8.56–8.66 (m, 2H). C NMR
1
3
, pp 67–79.
. Gladysz, J.; Hornby, J. L.; Garbe, J. E. J. Org. Chem.
978, 43, 1204–1208.
. (a) Klayman, D. L.; Griffin, T. S. J. Am. Chem. Soc. 1973,
5, 197–199; (b) Kienitz, C. O.; Th o¨ ne, C.; Jones, P. G.
5
6
(400 MHz, CDCl ): d 24.47, 125.21, 126.74, 127.65,
3
1
128.37, 128.48, 129.00, 130.41, 132.68, 135.12, 140.54.
Se NMR (300 MHz, CDCl ): d 202. GC–MS: m/z (%)
7
7
3
+
362 (M , 27), 282 (50), 267 (30), 220 (26), 141 (89), 115
9
Inorg. Chem. 1996, 35, 3990–3997.
. Krief, A.; Derock, M. Tetrahedron Lett. 2002, 43, 3083–
(100), 89 (12), 69 (14). Anal. Calcd for C H Se: C, 73.14;
2
2
18
7
8
H, 5.01. Found: C, 73.23; H, 5.32.
2
0
3086.
Red compound (diselenide) 10: yield: 0.15 g (7%). Mp
120–122 °C. Anal. Calcd for C H Se : C, 60.03; H, 4.11.
. (a) Syper, L.; Mlochowski, J. Tetrahedron 1988, 44, 6119–
6130; (b) Thompson, D. P.; Boudjouk, P. J. Org. Chem.
2
2
18
2
1
Found: C, 60.23; H, 4.37. H NMR (300 MHz, CDCl ): d
3
1
988, 53, 2109–2112.
2.27 (s, 6H), 7.24 (d, J = 8.8 Hz, 2H), 7.14–7.40 (m, 4H),
7.69 (dd, J = 8.1, 8.3 Hz, 4H), 8.14 (d, J = 8.4 Hz, 2H).
9
. (a) Sandman, D. J.; Stark, J. C.; Foxman, B. M.
Organometallics 1982, 1, 739–742; (b) Sandman, D. J.;
Stark, J. C.; Acampora, L. A.; Gagne, P. Organometallics
7
7
Se NMR (300 MHz, CDCl ): d 355.
3
24. Schlosser, M. Tetrahedron 1994, 50, 5845–6128.
25. Mugesh, G.; Singh, H. B. Acc. Chem. Res. 2002, 35, 226–
236.
1983, 2, 549–551.
1
0. (a) Bates, C. M.; Morley, C. P.; Hursthouse, M. B.; Malik,
K. M. A. J. Organomet. Chem. 1995, 489, C60–C61; (b)
Apte, S. D.; Singh, H. B.; Butcher, R. J. J. Chem. Res. (S)
26. Typical procedure for the reaction of dilithiated benzamides
with SeCl : a stirred solution of benzamide (5 mmol) in
30 mL THF was treated dropwise with a 1.6 M hexane
2
2000, 160–161; J. Chem. Res. (M) 2000, 0559–0569; (c)
Panda, A.; Menon, S. C.; Singh, H. B.; Butcher, R. J. J.
Organomet. Chem. 2001, 623, 87–94.
1. Foss, O. Inorg. Synth. 1953, 4, 88–93.
2. (a) Cordes, A. W.; Glarum, S. H.; Haddon, R. C.;
Hallford, R.; Hicks, R. G.; Kennepohl, D. K.; Oakley, R.
solution of n-BuLi (10 mmol) at 0 °C. The resulting solution
was allowed to warm to rt and stirred for 2 h at this
temperature. SeCl2 (2.5 mmol) solution, prepared sepa-
rately in a three-necked flask, was added to the dilithiated
benzamide solution dropwise at ꢀ78 °C. The resulting
1
1

S. S. Zade et al. / Tetrahedron Letters 46 (2005) 665–669
(60%). Mp 206–208. H NMR (300 MHz, CDCl
1.46 (m, 12H), 1.58–1.74 (m, 4H), 1.84–1.96 (m, 4H), 3.82–
669
1
solution was then allowed to warm to rt. The reaction
mixture was poured into water and extracted with dichlo-
romethane. The organic layer was filtered through Celite,
and dried over sodium sulfate. Evaporation of the solvent
afforded a colorless solid, which was purified by silica gel
column chromatography using dichloromethane as eluent.
7. (a) Weber, R.; Renson, M. Bull. Soc. Chim. Fr. 1976,
3
): d 1.00–
3.96 (m, 2H), 6.32 (d, J = 8.0 Hz, 2H), 7.20–7.40 (s, 6H),
7.64 (dd, J = 7.2, 1.4 Hz, 2H). C NMR (400 MHz,
CDCl ): d 24.98, 25.70, 32.98, 49.00, 127.85, 128.81,
131.28, 134.77, 137.66, 167.36. Anal. Calcd for
C H N O Se: C, 64.60; H, 6.66; N, 5.79. Found: C,
64.10; H, 6.38; N, 6.05.
1
3
3
2
2
6
32
2
2
1
124–1126; (b) Lambert, C.; Welter, A.; Christiaens, L. E.;
Dereu, N. Synth. Commun. 1991, 21, 85–98; (c) Christia-
ens, L. E.; Wirtz, P. Eur. Pat. Appl. EP 44453, 1982;
Chem. Abstr. 1982, 96, 199699v; (d) Engman, L.; Hallberg,
A. J. Org. Chem. 1989, 54, 2964–2965; (e) Fong, M. C.;
Schiesser, C. H. Tetrahedron Lett. 1995, 36, 7329–7332; (f)
Fong, M. C.; Schiesser, C. H. J. Org. Chem. 1997, 62,
30. (a) Christov, V. C.; Ivanov, I. K. Heterocycl. Commun.
2003, 9, 629–634; (b) Osajda, M.; Mlochowski, J. Synth.
Commun. 2003, 33, 1301–1307; (c) Kloc, K.; Osajda, M.;
Mlochowski, J. Chem. Lett. 2001, 826–827; (d) Potapov,
V. A.; Amosova, S. V.; Petrov, B. V.; Starkova, A. A.;
Malyushenko, R. N. Sulfur Lett. 1998, 21, 109–114; (e)
Back, T. G.; Dyck, B. P.; Nan, S. Tetrahedron 1999, 55,
3191–3208.
31. For a detailed description see supporting information.
Crystallographic data (excluding structure factors) have
been deposited with the Cambridge Crystallographic Data
Centre as supplementary publication number CCDC-
250001. Copies of the data can be obtained, free of
charge, on application to CCDC, 12 Union Road,
Cambridge CB2 1EZ, UK [fax: +44(0) 1223 336033 or
e-mail: deposit@ccdc.cam.ac.uk].
3
103–3108; (g) Jacquemin, P. V.; Christiaens, L. E.;
Renson, M. J.; Evers, M. J.; Dereu, N. Tetrahedron Lett.
992, 33, 3863–3866; (h) Kloc, K.; Mlochowski, J.;
Osajda, M.; Syper, L.; Wojtowicz, H. Tetrahedron Lett.
002, 43, 4071–4074.
8. Lesser, R.; Weiss, R. Ber. Dtsch. Chem. Ges. 1924, 57,
077–1082.
1
2
2
2
1
9. Monoselenide 19 was prepared using the typical procedure
as a brown solid, which was purified by chromatography
on silica gel (dichloromethane) to afford a white solid