A simple method for the synthesis of substituted benzylic ketones: Homologation of aldehydes via the in situ generation of aryldiazomethanes from aromatic aldehydes

Article abstract of DOI:10.1021/jo000446y

A general method for the homologation of aldehydes to benzylic ketones has been developed. Aryldiazomethanes were generated in situ in the presence of an aldehyde by simply heating the tosylhydrazones of aromatic aldehydes in the presence of a stoichiometric amount of base in polar protic solvents. The resulting polar protic solvent promoted homologation afforded benzylic ketones in moderate to excellent yields with a variety of aldehydes. Isolation of the tosylhydrazones was not necessary; they could be prepared in ethanol and carried through the sequence without isolation. This methodology allows easy access to a wide variety of substituted aryldiazomethanes that would be difficult, or even impossible, to prepare via conventional methods and circumvents the toxicity and stability problems associated with the isolation and/or handling solutions of aryldiazomethanes.

Full text of DOI:10.1021/jo000446y

6458
J . Org. Chem. 2000, 65, 6458-6461
A Sim p le Meth od for th e Syn th esis of Su bstitu ted Ben zylic
Keton es: Hom ologa tion of Ald eh yd es via th e in Situ Gen er a tion of
Ar yld ia zom eth a n es fr om Ar om a tic Ald eh yd es
Steven R. Angle* and Martin L. Neitzel
Department of Chemistry, University of CaliforniasRiverside, Riverside, California 92521-0403
steven.angle@ucr.edu
Received March 24, 2000
A general method for the homologation of aldehydes to benzylic ketones has been developed.
Aryldiazomethanes were generated in situ in the presence of an aldehyde by simply heating the
tosylhydrazones of aromatic aldehydes in the presence of a stoichiometric amount of base in polar
protic solvents. The resulting polar protic solvent promoted homologation afforded benzylic ketones
in moderate to excellent yields with a variety of aldehydes. Isolation of the tosylhydrazones was
not necessary; they could be prepared in ethanol and carried through the sequence without isolation.
This methodology allows easy access to a wide variety of substituted aryldiazomethanes that would
be difficult, or even impossible, to prepare via conventional methods and circumvents the toxicity
and stability problems associated with the isolation and/or handling solutions of aryldiazomethanes.
In tr od u ction
excellent yields of benzyl ketones. Sterically demanding
aldehydes, such as pivalaldehyde, failed to afford ho-
mologation products. We report here a general method
for the in situ preparation of aryldiazomethanes that
allows a one-step homologation of an aldehyde to a
benzylic ketone and avoids isolation or handling solutions
of the potentially toxic and explosive aryldiazomethanes.5
The conversion of aldehydes to ketones can be ac-
complished by a variety of methods, the most common
being a two-step process involving addition of a Grignard
reagent to the aldehyde followed by oxidation to the
ketone.1 This conversion can also be accomplished in a
single step by reaction of an aldehyde with a diazo com-
pound in the presence of a Lewis acid or other acti-
vating agent (eq 1).2 The relatively stable diazo com-
pounds trimethylsilyldiazomethane3 and ethyl diazoac-
etate4 have both seen wide application in the one-step
homologation of aldehydes to methyl ketones and â-ke-
toesters, respectively (eq 1). Aryldiazomethanes5,6 were
used by Anselme and co-workers for the one-step ho-
mologation of aldehydes 1 to benzylic ketones 2 (R′ )
aryl).7 These workers found that treatment of aryl and
primary alkyl aldehydes with an aryldiazomethane in
ether saturated with lithium bromide afforded good to
To date, it has not been possible to carry out the
synthesis of an aryl diazo compound and homologation
to a benzylic ketone in the same reaction flask due to
the incompatibility of the reaction conditions for the two
steps: synthesis of the aryldiazo compound requires a
protic solvent,5,6 and the previously reported homologa-
tion reactions require aprotic solvents and anhydrous
conditions.7,8 For example, aryldiazomethanes are easily
prepared by Bamford-Stevens reaction of the tosylhy-
drazones of aromatic aldehydes in ethylene glycol and
other alcohol solvents6 whereas Anselme’s homologation
with aryldiazomethanes is carried out in anhydrous
ether.7
(1) Smith, M. B. Organic Synthesis; McGraw-Hill: New York, 1994.
(2) For leading references and reviews see: (a) Gutsche, C. D. Org.
React. 1954, 8, 364-429. (b) Wulfman, D. S.; Linstrumelle, G.; Cooper,
C. F. In The Chemistry of Diazonium and Diazo Groups; Patai, S., Ed.;
Interscience: New York, 1978; p 821. (c) Maruoka, K.; Concepcion, A.
B.; Yamamoto, H. J . Org. Chem. 1994, 59, 4725-4726. (e) Maruoka,
K.; Concepcion, A. B.; Yamamoto, H. Synthesis 1994, 1283-1290.
(3) (a) Aoyama, T. Yakugaku Zasshi (J ournal of the Pharmaceutical
Society of J apan) 1991, 111, 570-584. (b) Podlech, J . J . Prakt. Chem./
Chem.- Ztg. 1998, 340, 679-682. (c) Hashimoto, N.; Aoyama, T.;
Shioiri, T. Tetrahedron Lett. 1980, 21, 4619-4622. (d) Werner, R. M.;
Shokek, O.; Davis, J . T. J . Org. Chem. 1997, 62, 8243-8246.
(4) (a) Holmquist, C. R.; Roskamp, E. J . J . Org. Chem. 1989, 54,
3258-3260. (b) Holmquist, C. R.; Roskamp, E. J . Tetrahedron Lett.
1992, 33, 1131-1134. (c) Kanemasa, S.; Kanai, T.; Araki, T.; Wada,
E. Tetrahedron Lett. 1999, 40, 5055-5058.
(5) For methods to prepare aryldiazomethanes see: (a) Creary, X.
J . Am. Chem. Soc. 1980, 102, 1611-1618. (b) Creary, X. Org. Synth.
1985, 64, 207-216. (c) Overberger, C. G.; Anselme, J .-P. J . Org. Chem.
1963, 28, 592-593. (d) Kaufman, G. M.; Smith, J . A.; VanderStouw,
G. G.; Shechter, H. J . Am. Chem. Soc. 1965, 87, 935-937.
(6) Bamford, W. R.; Stevens, T. S. J . Chem. Soc. 1952, 4735-4740.
This reference contains a study following the conversion of benzalde-
hyde tosylhydrazone to phenyldiazomethane in ethanol and monitors
its concentration at periodic intervals over 24 h.
Resu lts a n d Discu ssion
Bradley and co-workers have shown that methanol
promotes the addition of diazomethane to aldehydes and
ketones,9 and it seemed reasonable that the reaction of
phenyldiazomethane might also be facilitated by metha-
nol. If this were the case, it seemed likely that methanol,
or other alcohols, might serve a dual role as solvent for
aryldiazomethane synthesis and promoter for the addi-
tion of the diazo compound to the aldehyde. In an effort
(8) Mahmood, S. J .; Saha, A. K.; Hossain, M. M. Tetrahedron 1998,
54, 349-358.
(7) Loeschorn, C. A.; Nakajima, M.; McCloskey, P.; Anselme, J .-P.
J . Org. Chem. 1983, 48, 4407-4410.
(9) Bradley, J . N.; Cowell, G. W.; Ledwith, A. J . Chem. Soc. 1964,
4334-4339.
10.1021/jo000446y CCC: $19.00 © 2000 American Chemical Society
Published on Web 09/08/2000

Homologation of Aldehydes
Ta ble 1. Syn th esis of Ben zyl Keton es
J . Org. Chem., Vol. 65, No. 20, 2000 6459
Ta ble 2. Rea ction s of Su bstitu ted Ar yld ia zom eth a n es
a
Yield refers to the 16 to 17 transformation and is based on
benzaldehyde with 2 equiv of hydrazone. bKetone 8 was isolated
in 25% yield. The hydrazone was prepared in situ and the yield
c
is for 15d to 17d .
ometry appears to be due to the faster side reaction of
phenyldiazomethane with methanol over ethanol.11 All
other factors being equal, ethanol is the solvent of choice;
purification is easier due to fewer hydrazone derived
byproducts.
a
2 equiv of hydrazone were used in reactions run in EtOH and
b
3 equiv were used for reactions in MeOH. In MeOH the reaction
mixture contained byproducts that made purification difficult.
to test this notion, aldehyde 310 was treated with phen-
yldiazomethane (2 equiv) in methanol (rt, 2 days) to
afford benzyl ketone 4 in 78% yield after flash chroma-
tography (eq 2). This result provides an opportunity for
realizing a one-pot aldehyde to ketone homologation
reaction.
The examples in Table 1 show that the substituents R
to the aldehyde have a direct effect on the yield of the
homologation reaction. The more bulky the substituent,
the higher the yield of benzyl ketone. It is worth noting
that the reaction conditions are also compatible with an
acetonide (Table 1, entry 5); however, racemization of the
stereogenic center did occur. This method is complemen-
tary with the LiBr-promoted reactions. Anselme was
unable to isolate benzyl ketone products when aldehydes
5, 7, and 9 were reacted with phenyldiazomethane,7
whereas we obtain good to excellent yields of benzyl
ketones from these aldehydes. Our yields are lowest with
nonbranched aliphatic aldehyde 13, and these substrates
afforded the highest yields in the LiBr-promoted reac-
tions.7 Despite the decrease in yield for unhindered
aldehydes, our procedure provides considerable advan-
tage over existing methodology due to the simplicity and
safety of the reaction conditions.
The one-pot homologation of a series of readily avail-
able aldehydes with phenyldiazomethane is summarized
in Table 1. Heating a solution of the aldehyde and
benzaldehyde tosylhydrazone (2 equiv) in methanol or
ethanol solvent with 2 equiv of the appropriate alkoxide
resulted in the slow generation of phenyldiazomethane.6
The reaction mixture was stirred until the pink color of
the phenyldiazomethane had faded, indicating its com-
plete consumption by reaction with the alcohol solvent
and thereby avoiding the potential hazard of isolating
the diazo compound. Concentration, aqueous workup, and
flash chromatography afforded the benzylic ketones in
the yields shown. Reactions carried out in methanol
required 3 equiv of hydrazone for the complete reaction
of aldehyde, whereas those in ethanol required only 2
equiv of hydrazone. The reason for the different stoichi-
Substituted aryldiazo compounds can be prepared in
situ and reacted with an aldehyde using this methodol-
ogy. Table 2 shows several examples where readily
available aldehydes 15 were converted to the correspond-
ing tosylhydrazones 16 and then reacted with benzalde-
hyde to afford benzylic ketones 17. In the case of 15a ,
(11) For discussions of the stability of diazo compounds to protic
solvents: (a) Finneman, J . I.; Fishbein, J . C. J . Org. Chem. 1994, 59,
6251-6256. (b) Finneman, J . I.; Fishbein, J . C. J . Am. Chem. Soc. 1995,
117, 4228-4239. See also ref 6.
(10) Angle, S. R.; Neitzel, M. L. J . Org. Chem. 1999, 64, 8754-8757.

6460 J . Org. Chem., Vol. 65, No. 20, 2000
Angle and Neitzel
Ta ble 3. Effect of Solven t on Hom ologa tion
equiv of
yield of
entry
16
cond.
solvent
MeOH
base
17, %
1
2
3
4
5
6
3
3
3
2
2
3
28 h, 50 °C
0.5 h, 80 °C (HOCH2)2
1 h, 90 °C
21 h, 60 °C
4 h, 60 °C
6 d, 60 °C
NaOMe
NaOR
77
71
76
79
21
<3
H2O
NaOHa
95% EtOH NaOHb
formamide NaOHb
DMSO
NaOHb
a
1 M aqueous solution. bPellets.
the product 17a reacted with phenyldiazomethane to
afford 8 in 25% yield. This is the only example where
products derived from subsequent reaction of the initial
homologation product were observed. The preparation of
the acetal containing aryldiazomethane in entry 4 was
problematic due to difficulties in isolating tosylhydrazone
16d . To circumvent this problem, the corresponding
aldehyde, 15d , was reacted with tosylhydrazide in etha-
nol to afford the hydrazone, and then sodium ethoxide
(2 equiv) and benzaldehyde were added. Heating this
solution for 2 days at 55 °C afforded a 52% yield of ketone
17d .
In an attempt to investigate the range of solvents
compatible with the reaction, benzaldehyde was homolo-
gated with p-chlorobenzaldehyde tosylhydrazone using
a variety of polar protic solvents (Table 3). As can be seen,
the yields of benzylic ketone 17e range from 71% to 79%
when polar protic solvents are used. Polar aprotic sol-
vents formamide and DMSO afforded 17e in 21% and
<3% yield, respectively. Thus, the reaction appears to
require a polar protic solvent for good yields of homolo-
gation products.
This new methodology is versatile and convenient. For
example, hydrazone 16e (Table 3, entry 3) was simply
dissolved in 1 M aqueous NaOH and then heated with
benzaldehyde. Aqueous workup and flash chromatogra-
phy afforded 17e in 76% yield. As outlined in entry 4,
neat NaOH was added to the hydrazone in 95% ethanol
and then heated with benzaldehyde to afford ketone 17e
in a 79% yield after aqueous workup and flash chroma-
tography.
The in situ formation of tosylhydrazones from aromatic
aldehydes followed by base-promoted Bamford-Stevens
reaction6 was already used to advantage in the synthesis
of 17d from 15d and benzaldehyde (Table 2, entry 4).
This methodology provides the opportunity to utilize
aryldiazomethanes containing electron-releasing substit-
uents that would be difficult, or even impossible,11,12 to
prepare via conventional methods.5,6 To illustrate the
generality of this method, aldehyde 18 was reacted with
tosylhydrazide in ethanol to effect hydrazone formation
(eq 3). Addition of sodium ethoxide followed by p-
methoxybenzaldehyde, 15c, and heating for 39 h afforded
ketone 19 in 60% isolated yield.
moderate to excellent yields of benzylic ketones. The need
to isolate and/or handle solutions of diazo compounds is
eliminated and excess reagent is destroyed by reaction
with solvent prior to workup. Efforts to exploit this
methodology in the synthesis of natural products is
currently under study.
Exp er im en ta l Section
Gen er a l In for m a tion . The starting aldehydes were pur-
chased from Aldrich or Acros. Tosylhydrazones were prepared
according to literature procedures.6 All capillary GCs were run
on a 25 m HP 1 (methyl silicone column) with a flame ioni-
zation detector. Unless stated otherwise, the following stan-
dard parameters were used: initial temperature ) 40 °C; final
temperature ) 170 °C; heating rate ) 10 °C per minute; injec-
tor temperature ) 150 °C; detector temperature ) 250 °C.
3,3-Dim e t h yl-1-p h e n yl-4-(t r ie t h ylsilyl)oxy-2-b u t a -
n on e (4). Freshly distilled phenyldiazomethane (0.46 mmol,
54 mg, Ca u tion : Dia zo com p ou n d s a r e toxic a n d p oten -
tia lly exp losive) was added to aldehyde 3 (0.23 mmol, 50 mg)
in anhydrous methanol (0.1 M). The reaction was protected
from light and stirred at room temperature for 48 h at which
time the red color of the phenyldiazomethane had disappeared.
The solvent was removed in vacuo, and the resulting oil was
diluted with H2O (100 mL) and CH2Cl2 (100 mL). The aqueous
layer was extracted with CH2Cl2 (2 × 50 mL) and the combined
organic extracts were dried (MgSO4) and concentrated to afford
81 mg of a light yellow oil. Flash chromatography (silica gel,
hexanes/ethyl acetate) afforded the known10 benzyl ketone 4
(54 mg, 78%) as a colorless oil.
Gen er a l P r oced u r e for th e P r ep a r a tion of Keton es 6,
8, 10, 12, 14, 17a -c, a n d 17e. A 2 M solution of the sodium
alkoxide or sodium hydroxide (see Tables 1-3 for details;
sodium alkoxides were freshly prepared from sodium (92 mg,
4.0 mmol) and the alcohol (20 mL)) was added to benzaldehyde
tosylhydrazone or hydrazones 16 (4.0 mmol) in alcohol solvent
(20 mL). The resulting solution was protected from light, the
appropriate aldehyde (2.0 mmol) was added, and the reaction
mixture was heated for the time indicated in each experimen-
tal (the light red color of the aryldiazomethane had disap-
peared). In the case of reactions run in methanol and ethanol,
the solvent was removed in vacuo. The residue was diluted
with H2O (100 mL) and CHCl3, (50 mL). The aqueous layer
was extracted with CHCl3, (2 × 50 mL), and the combined
organic extracts were dried (MgSO4) and concentrated to afford
crude products. Flash chromatography (silica gel, hexanes/
ethyl acetate) afforded the product ketones in the yields
indicated.
3,3-Dim eth yl-1-p h en yl-2-bu ta n on e (6). According to the
general procedure the reaction mixture was heated for 72 h
at 50 °C to afford the known13 ketone 6 as a light yellow oil in
90% yield: purity by GC ) 96.7% (tR ) 22.40 min; heating
rate ) 5 °C per min; detector temperature ) 200 °C).
1,1,3-Tr ip h en yl-2-p r op a n on e (8). According to the gen-
eral procedure the reaction mixture was heated for 4 h at 65
Con clu sion
We have developed a general method for the homolo-
gation of an aldehyde with an arylaldehyde to afford
(12) Closs, G. L.; Moss, R. A. J . Am. Chem. Soc. 1964, 86, 4042-
4053.

Homologation of Aldehydes
J . Org. Chem., Vol. 65, No. 20, 2000 6461
°C to afford the known14 ketone 8 as a white solid in 84% yield;
mp 73-74 °C, (no lit. melting point14); purity by GC ) 98.4%
(tR ) 32.29 min; final temperature ) 220 °C, injector temper-
ature ) 220 °C).
3-Meth yl-1-p h en yl-2-bu ta n on e (10). According to the
general procedure the reaction mixture was heated for 24 h
at 50 °C to afford the known15 ketone 10 as a clear oil in 56%
yield: purity by GC ) 98.2% (tR ) 20.75 min; heating rate )
5 °C per min; detector temperature ) 200 °C).
3,4-O-Isop r op ylid en e-1-p h en yl-2-bu ta n on e (12). Accord-
ing to the general procedure the reaction mixture was heated
for 0.75 h at 50 °C to afford ketone 12 as a clear oil in 66%
yield. Chiral shift study using Eu(hfc)3 showed the product to
be racemic: purity by GC ) 88.9% (tR ) 21.30 min; injector
temperature ) 170 °C, detector temperature ) 225 °C); 1H
NMR (300 MHz, CDCl3)δ 7.29-7.12 (m, 5H), 4.45 (dd, J ) 7.7,
5.6 Hz, 1H), 4.09 (dd, J ) 8.7, 7.7 Hz, 1H), 3.95 (dd, J ) 8.7,
5.6 Hz, 1H), 3.85 (ABq, J ) 15.4 Hz, ∆ν ) 26.1 Hz, 2H), 1.44
(s, 3H), 1.34 (s, 3H); 13C NMR (75 MHz, CDCl3)δ 207.7, 133.2,
129.6, 128.6, 127.0, 111.0, 79.9, 66.4, 45.4, 26.0, 25.0; IR (neat)
2988, 1721, 1373, 1151, 1066 cm-1; MS (CI, NH3) m/z 221 (100,
MH+), 101 (23); HRMS calcd for C13H17O3 (M+H) 221.1177,
found 221.1170.
2-(4-Meth oxyp h en yl)a cetop h en on e (17c). According to
the general procedure the reaction mixture was heated for 48
h at 50 °C to afford the known18 ketone 17c as clear plates in
63% yield: mp 93-94 °C, (lit.18 95.5-96 °C); purity by GC )
98.4% (tR ) 27.34 min; detector temperature ) 200 °C).
2-(4-Ch lor op h en yl)a cetop h en on e (17e). According to the
general procedure the reaction mixture was heated for 40 h
at 60 °C to afford the known18 ketone 17e as clear plates in
81% yield: mp 129-130 °C, (lit.18 137.5-139 °C); purity by
GC ) 95.9% (tR ) 25.72 min; final temperature ) 200 °C).
Gen er a l P r oced u r e for th e P r ep a r a tion of Keton es
17d a n d 19. The aldehyde (18 or 15d , 4.0 mmol) was added
to toluenesulfonhydrazide (0.745 g, 4.0 mmol) in absol ethanol
(20 mL), and the resulting solution was stirred at room
temperature for 40 min. A solution of 2 M sodium ethoxide
(20 mL, freshly prepared from sodium and ethanol) was then
added, the resulting solution was heated to 55 °C, and
aldehyde 15a or 15c (2.0 mmol) was added. The reaction was
protected from light and stirred at 55 °C for the time indicated
in each experimental (the light red color of the aryldiaz-
omethane had disappeared). Workup and chromatography as
noted above afforded products 17d and 19 in the yields
indicated.
2-P ip er on yla cetop h en on e (17d ). According to the general
procedure the reaction mixture was heated for 48 h at 50 °C
to afford the known19 ketone 17d as a clear oil in 52% yield:
purity by GC ) 96.1% (tR ) 26.38 min; final temperature )
220 °C, injector temperature ) 185 °C).
1,4-Dip h en yl-2-bu ta n on e (14). Heated for 6 h at 60 °C to
afford the known16 ketone 14 as a white solid 44% yield: mp
o
41-43 C, (lit.16b 41-42 °C); purity by GC ) 99.9% (tR ) 21.57
min; final temperature ) 220 °C, injector temperature ) 220
°C).
2-(2,3,4-Tr im et h oxyp h en yl)-4-m et h oxya cet op h en on e
(19). According to the general procedure the reaction mixture
was heated for 39 h at 50 °C; white solid, mp 80-85 °C; 60%
yield; purity by GC ) 99.9% (tR ) 24.43 min; heating rate )
20 °C per min; final temperature ) 250 °C, injector temper-
2-P h en yla cetop h en on e (17a ). According to the general
procedure the reaction mixture was heated for 48 h at 55 °C
to afford the known7,17 ketone 17a as a white needles (ethanol)
in 42% yield: mp 54-55 °C, (lit.7 55-56 °C); purity by GC )
99.9% (tR ) 21.12 min; final temperature ) 220 °C, injector
temperature ) 170 °C, detector temperature ) 250 °C).
2-(4-Meth ylp h en yl)a cetop h en on e (17b). According to the
general procedure the reaction mixture was heated for 48 h
at 50 °C to afford the known18 ketone 17b as clear plates in
1
ature ) 220 °C); H NMR (300 MHz, CDCl3)δ 8.00 (dm, J )
9.2 Hz, 2H), 6.93 (dm, J ) 8.7 Hz, 2H), 6.47 (s, 2H), 4.16 (s,
2H), 3.86 (s, 3H), 3.82 (s, 6H), 3.81 (s, 3H); 13C NMR (75 MHz,
CDCl3)δ 196.1, 163.6, 153.3, 136.8, 130.9, 130.5, 129.6, 113.8,
106.4, 60.8, 56.1, 55.4, 45.4; IR (KBr) 2935, 2834, 1675, 1596,
1509, 1122 cm-1; MS (EI, 70 eV) m/z 316(14, M+), 181 (15),
135 (100); HRMS calcd for C18H20O5 316.1311, found 316.1301.
o
88% yield: mp 95-96 C, (lit.18 97.5-99 °C); purity by GC )
99.9% (tR ) 37.46 min; detector temperature ) 200 °C).
Ack n ow led gm en t. We thank The National Science
Foundation CHE-9528266 for financial support.
(13) Alonso, E.; Guijarro, D.; Martinez, P.; Ramon, D. J .; Yus, M.
Tetrahedron 1999, 55, 11027-11038.
(14) Miyoshi, N.; Takeuchi, S.; Ohgo, Y. Bull. Chem. Soc. J pn. 1994,
67, 445-451.
Su p p or tin g In for m a tion Ava ila ble: Copies of 1H and 13C
NMR spectra for compounds 6, 8, 10, 12, 14, 17a -e, and 19.
This material is available free of charge via the Internet at
http://pubs.acs.org.
(15) Mattson, M. N.; Rapoport, H. J . Org. Chem. 1996, 61, 6071-
6074.
(16) (a) Murata, Y.; Inomata, K.; Kinoshita, H.; Kotake, H. Bull.Chem.
Soc. J pn. 1983, 56, 2539-2540. (b) Shankaran, K.; Talekar, D. G.; Rao,
A. S. Indian J . Chem. 1982, 21B, 408-410.
(17) Compound 17a , deoxybenzoin, is commercially available from
Aldrich.
J O000446Y
(18) Miyashita, A.; Matsuoka, Y.; Suzuki, Y.; Iwamoto, K.; Hi-
gashino, T. Chem. Pharm. Bull. 1997, 45, 1235-1242.
(19) J ung, M. E.; Lam, P.; Mansuri, M. M.; Speltz, L. M. J . Org.
Chem. 1985, 50, 1087-1105.