257-07-8

Basic information

• Product Name: Dibenz-(b,f)-1,4-oxazephine
• Synonyms: DIBENZO(B,F)-1,4OXAZEPINE;DIBENZ-1,4-OXAZEPINE;EA-3547;benzo[b][1,5]benzoxazepine;Dibenz-(b,f)-1,4-oxazephine;dibenz(b,f)(1,4)oxazepine;benzo[b][1,4]benzoxazepine
• CAS NO: 257-07-8
• Molecular Formula: C₁₃H₉NO
• Molecular Weight: 195.21666
• Mol File: 257-07-8.mol
• Article Data: 20

Chemical Properties

• Boiling Point: 331.88°C (rough estimate)
• Flash Point: 125°C
• Appearance: /
• Density: 1.1266 (rough estimate)
• Vapor Pressure: 0.000342mmHg at 25°C
• Refractive Index: 1.6060 (estimate)
• CAS DataBase Reference: Dibenz-(b,f)-1,4-oxazephine(CAS DataBase Reference)
• NIST Chemistry Reference: Dibenz-(b,f)-1,4-oxazephine(257-07-8)
• EPA Substance Registry System: Dibenz-(b,f)-1,4-oxazephine(257-07-8)

Safety Data

• Hazardous Substances Data: 257-07-8(Hazardous Substances Data)

Usage

Description

Agent CR, dibenz-(b,f)-1,4-oxazepine, is a pale-yellow, crystalline solid, which has a melting point of 163°F (72°C). It has a pepper-like odor and is only used in solution for dissemination in liquid dispensers. Solutions consist of 0.1% of CR in 80 parts of propylene glycol and 20 parts water. CR is an eye irritant in organic solutions at concentrations of 0.0025% or lower. Agent CR is less toxic when inhaled, but has more profound skin effects, which are longer lasting. It is a persistent agent when released in the environment and deposited on clothing.

General Description

Colorless liquid, odorless to fruity.

Reactivity Profile

As an amine, Dibenz-(b,f)-1,4-oxazephine probably behaves less as a base than other aliphatic amines as due to Dibenz-(b,f)-1,4-oxazephine cyclic structure. However Dibenz-(b,f)-1,4-oxazephine will react as a weak base.

Health Hazard

Median incapacitating dose: 0.15. Eye/skin toxicity: Highly irritating; not toxic. Rate of action: Instantaneous. Physiological action: Irritates skin, eyes, nose, and throat. Detoxification rate: Moderate. (ANSER)

Safety Profile

Poison by intraperitoneal and intravenous routes. Moderately toxic by ingestion and inhalation. Experimental teratogenic and reproductive effects. A human skin and eye irritant. Questionable carcinogen with experimental carcinogenic and tumorigenic data. When heated to decomposition it emits toxic fumes of NOx.

InChI:InChI=1/C13H9NO/c1-3-7-12-10(5-1)9-14-11-6-2-4-8-13(11)15-12/h1-9H

Synthetic route

2-Fluorobenzaldehyde (446-52-6) + 2-amino-phenol (95-55-6) → dibenz[b,f][1,4]oxazepine (257-07-8) + 2-(2-fluorophenyl)benzo[d]oxazole (212758-52-6)

Conditions	Yield
With oxygen; 1,3-diethyl-1H-benzo[d]imidazol-3-ium bromide; sodium hydroxide In o-xylene; para-xylene; m-xylene at 120℃; for 10h; Molecular sieve; Green chemistry;	A 25% B 65%

2-Fluorobenzaldehyde (446-52-6) + 2-amino-phenol (95-55-6) → dibenz[b,f][1,4]oxazepine (257-07-8)

Conditions	Yield
With poly(ethylene glycol)-400; potassium carbonate at 100℃; for 8h; Product distribution; Further Variations:; Reagents; Solvents; Temperatures; time;	89%
Stage #1: 2-amino-phenol In polyethylene glycol (300) at 50℃; for 0.5h; Stage #2: 2-Fluorobenzaldehyde In polyethylene glycol (300) at 50℃; for 10h; Stage #3: With potassium carbonate In polyethylene glycol (300) at 100℃; for 10h;	80%
With potassium carbonate at 100℃; Sealed tube;	58%

2-[(2-chlorobenzylidene)amino]phenol (6266-10-0) → dibenz[b,f][1,4]oxazepine (257-07-8)

Conditions	Yield
Stage #1: 2-[(2-chlorobenzylidene)amino]phenol With potassium hydroxide In methanol at 20℃; for 0.583333h; Stage #2: In dimethyl sulfoxide at 120℃; for 2h; Further stages.;	75%
Stage #1: 2-[(2-chlorobenzylidene)amino]phenol With potassium hydroxide In methanol at 20℃; for 1h; Stage #2: In dimethyl sulfoxide at 150℃; for 6h;
Multi-step reaction with 2 steps 1: N,N-dimethyl-formamide / 140 °C / Microwave irradiation 2: N,N-dimethyl-formamide / 140 °C / Microwave irradiation View Scheme

2-chloro-benzaldehyde (89-98-5) + 2-amino-phenol (95-55-6) → dibenz[b,f][1,4]oxazepine (257-07-8)

Conditions	Yield
With potassium hydroxide In N,N-dimethyl-formamide at 120℃; for 0.1h; Temperature; Reagent/catalyst; Microwave irradiation;	87%
Stage #1: 2-chloro-benzaldehyde; 2-amino-phenol In 5,5-dimethyl-1,3-cyclohexadiene for 2h; Reflux; Stage #2: In 5,5-dimethyl-1,3-cyclohexadiene at 120℃; for 24h; Stage #3: With sodium In 5,5-dimethyl-1,3-cyclohexadiene for 6h; Reflux;	75%

phenylacetylene (536-74-3) + 2-amino-phenol (95-55-6) → dibenz[b,f][1,4]oxazepine (257-07-8)

Conditions	Yield
With tetrabutylammonium acetate; palladium diacetate; 1,2-diamino-benzene In N,N-dimethyl-formamide at 120℃; Microwave irradiation;	82%

N-(2-phenoxyphenyl)formamide (2770-12-9) → dibenz[b,f][1,4]oxazepine (257-07-8)

Conditions	Yield
With polyphosphiric acid; trichlorophosphate at 120 - 130℃; for 2h; Cyclization;	75%

2-formamido-4'-tert-butyldiphenyl ester → dibenz[b,f][1,4]oxazepine (257-07-8)

Conditions	Yield
With polyphosphiric acid; trichlorophosphate at 120 - 130℃; for 2h; Cyclization;	56%

benzaldehyde (100-52-7) + 2-amino-phenol (95-55-6) → dibenz[b,f][1,4]oxazepine (257-07-8)

Conditions	Yield
With potassium carbonate at 100℃; for 5h;	68%

2-amino-phenol (95-55-6) → dibenz[b,f][1,4]oxazepine (257-07-8)

Conditions	Yield
Multi-step reaction with 3 steps 1: N,N-dimethyl-formamide / 140 °C / Microwave irradiation 2: N,N-dimethyl-formamide / 140 °C / Microwave irradiation 3: N,N-dimethyl-formamide / 140 °C / Microwave irradiation View Scheme
Multi-step reaction with 3 steps 1: N,N-dimethyl-formamide / 140 °C / Microwave irradiation 2: N,N-dimethyl-formamide / 140 °C / Microwave irradiation 3: N,N-dimethyl-formamide / 140 °C / Microwave irradiation View Scheme
Multi-step reaction with 3 steps 1: N,N-dimethyl-formamide / 140 °C / Microwave irradiation 2: N,N-dimethyl-formamide / 140 °C / Microwave irradiation 3: N,N-dimethyl-formamide / 140 °C / Microwave irradiation View Scheme

2-formamido-4'-tert-butyldiphenyl ester → dibenz[b,f][1,4]oxazepine (257-07-8) + 2-tert-butyl-dibenzo[b,f][1,4]oxazepine

Conditions	Yield
With polyphosphiric acid; trichlorophosphate at 120 - 130℃; for 2h; Cyclization;	A 23% B 31%

2-Fluorobenzaldehyde (446-52-6) → dibenz[b,f][1,4]oxazepine (257-07-8)

Conditions	Yield
Multi-step reaction with 3 steps 1: N,N-dimethyl-formamide / 140 °C / Microwave irradiation 2: N,N-dimethyl-formamide / 140 °C / Microwave irradiation 3: N,N-dimethyl-formamide / 140 °C / Microwave irradiation View Scheme
Multi-step reaction with 3 steps 1: potassium tert-butylate / N,N-dimethyl-formamide / 140 °C / Microwave irradiation 2: N,N-dimethyl-formamide / 140 °C / Microwave irradiation 3: N,N-dimethyl-formamide / 140 °C / Microwave irradiation View Scheme
Multi-step reaction with 3 steps 1: sodium hydrogencarbonate / N,N-dimethyl-formamide / 140 °C / Microwave irradiation 2: N,N-dimethyl-formamide / 140 °C / Microwave irradiation 3: N,N-dimethyl-formamide / 140 °C / Microwave irradiation View Scheme

2-(2-nitrophenoxy)benzaldehyde (66961-19-1) → dibenz[b,f][1,4]oxazepine (257-07-8)

Conditions	Yield
With iron In methanol; water for 6h; Reflux;

2-phenoxybenzamide (72084-13-0) → dibenz[b,f][1,4]oxazepine (257-07-8)

Conditions	Yield
With PPA at 120 - 130℃; Cyclization;

C13H9FNO(1-)*K(1+) → dibenz[b,f][1,4]oxazepine (257-07-8)

Conditions	Yield
In N,N-dimethyl-formamide at 140℃; Microwave irradiation;

C13H9FNO(1-)*Na(1+) → dibenz[b,f][1,4]oxazepine (257-07-8)

Conditions	Yield
In N,N-dimethyl-formamide at 140℃; Microwave irradiation;

C13H10FNO → dibenz[b,f][1,4]oxazepine (257-07-8)

Conditions	Yield
In N,N-dimethyl-formamide at 140℃; Microwave irradiation;

C13H10ClNO → dibenz[b,f][1,4]oxazepine (257-07-8)

Conditions	Yield
In N,N-dimethyl-formamide at 140℃; Microwave irradiation;

C13H10BrNO → dibenz[b,f][1,4]oxazepine (257-07-8)

Conditions	Yield
In N,N-dimethyl-formamide at 140℃; Microwave irradiation;

C13H10INO → dibenz[b,f][1,4]oxazepine (257-07-8)

Conditions	Yield
In N,N-dimethyl-formamide at 140℃; Microwave irradiation;

2-chloro-benzaldehyde (89-98-5) → dibenz[b,f][1,4]oxazepine (257-07-8)

Conditions	Yield
Multi-step reaction with 3 steps 1: N,N-dimethyl-formamide / 140 °C / Microwave irradiation 2: N,N-dimethyl-formamide / 140 °C / Microwave irradiation 3: N,N-dimethyl-formamide / 140 °C / Microwave irradiation View Scheme

ortho-bromobenzaldehyde (6630-33-7) → dibenz[b,f][1,4]oxazepine (257-07-8)

Conditions	Yield
Multi-step reaction with 3 steps 1: N,N-dimethyl-formamide / 140 °C / Microwave irradiation 2: N,N-dimethyl-formamide / 140 °C / Microwave irradiation 3: N,N-dimethyl-formamide / 140 °C / Microwave irradiation View Scheme

2-iodobenzaldehyde (26260-02-6) → dibenz[b,f][1,4]oxazepine (257-07-8)

Conditions	Yield
Multi-step reaction with 3 steps 1: N,N-dimethyl-formamide / 140 °C / Microwave irradiation 2: N,N-dimethyl-formamide / 140 °C / Microwave irradiation 3: N,N-dimethyl-formamide / 140 °C / Microwave irradiation View Scheme

C13H9FNO(1-)*K(1+) → dibenz[b,f][1,4]oxazepine (257-07-8)

Conditions	Yield
Multi-step reaction with 2 steps 1: N,N-dimethyl-formamide / 140 °C / Microwave irradiation 2: N,N-dimethyl-formamide / 140 °C / Microwave irradiation View Scheme

C13H9FNO(1-)*Na(1+) → dibenz[b,f][1,4]oxazepine (257-07-8)

Conditions	Yield
Multi-step reaction with 2 steps 1: N,N-dimethyl-formamide / 140 °C / Microwave irradiation 2: N,N-dimethyl-formamide / 140 °C / Microwave irradiation View Scheme

GRI 378898 (2805-76-7) → dibenz[b,f][1,4]oxazepine (257-07-8)

Conditions	Yield
Multi-step reaction with 2 steps 1: N,N-dimethyl-formamide / 140 °C / Microwave irradiation 2: N,N-dimethyl-formamide / 140 °C / Microwave irradiation View Scheme

2-Hydroxy-N-<2-brom-benzyliden>-anilin (36456-43-6) → dibenz[b,f][1,4]oxazepine (257-07-8)

Conditions	Yield
Multi-step reaction with 2 steps 1: N,N-dimethyl-formamide / 140 °C / Microwave irradiation 2: N,N-dimethyl-formamide / 140 °C / Microwave irradiation View Scheme

C13H10INO (218280-60-5) → dibenz[b,f][1,4]oxazepine (257-07-8)

Conditions	Yield
Multi-step reaction with 2 steps 1: N,N-dimethyl-formamide / 140 °C / Microwave irradiation 2: N,N-dimethyl-formamide / 140 °C / Microwave irradiation View Scheme

S-phenyl 2-diazoethanethiolate (72228-26-3) + dibenz[b,f][1,4]oxazepine (257-07-8) → (+/-)-trans-2-phenylthioazeto[1,2-d]dibenzo[b,f]oxazepin-1-one

Conditions	Yield
In toluene at 80℃; for 1.5h; Staudinger reaction;	99%
In benzene at 80℃; for 1h;	99%

indole (120-72-9) + dibenz[b,f][1,4]oxazepine (257-07-8) → 2-(2-(di(1H-indol-3-yl)methyl)phenoxy)aniline

Conditions	Yield
With trifluoroacetic acid In dichloromethane at 20℃; for 3h; Catalytic behavior; Solvent; Friedel-Crafts Alkylation;	99%

5-benzyloxy-1H-indole (1215-59-4) + dibenz[b,f][1,4]oxazepine (257-07-8) → 2-(2-(bis(5-(benzyloxy)-1H-indol-3-yl)methyl)phenoxy)aniline

Conditions	Yield
With trifluoroacetic acid In dichloromethane at 20℃; for 3h; Friedel-Crafts Alkylation;	99%

7-methyl-1H-indole (933-67-5) + dibenz[b,f][1,4]oxazepine (257-07-8) → 2-(2-(bis(7-methyl-1H-indol-3-yl)methyl)phenoxy)aniline

Conditions	Yield
With trifluoroacetic acid In dichloromethane at 20℃; for 3h; Friedel-Crafts Alkylation;	99%

dibenz[b,f][1,4]oxazepine (257-07-8) → 10H-dibenzo[b,f][1,4]oxazepin-11-one (3158-85-8)

Conditions	Yield
With dipotassium peroxodisulfate In ethanol; N,N-dimethyl-formamide at 50℃; for 1h; Time; Reagent/catalyst;	98%

5-methoxylindole (1006-94-6) + dibenz[b,f][1,4]oxazepine (257-07-8) → 2-(2-(bis(5-methoxy-1H-indol-3-yl)methyl)phenoxy)aniline

Conditions	Yield
With trifluoroacetic acid In dichloromethane at 20℃; for 1.5h; Friedel-Crafts Alkylation;	98%

1,5,7-trimethyl-3-diazooxindole + dibenz[b,f][1,4]oxazepine (257-07-8) → spiro[5,7-dimethyloxindole-imidazo-bis(tetrahydro-dibenzo[1,4]oxazepine)]

Conditions	Yield
With toluene-4-sulfonic acid In tetrahydrofuran at 15 - 20℃; for 24h; diastereoselective reaction;	93%

3-diazo-1-methyl-1,3-dihydro-indol-2-one (3265-14-3) + dibenz[b,f][1,4]oxazepine (257-07-8) → spiro[1-methyloxindole-imidazo-bis(tetrahydro-dibenzo[1,4]oxazepine)]

Conditions	Yield
With toluene-4-sulfonic acid In tetrahydrofuran at 15 - 20℃; for 24h; diastereoselective reaction;	93%

3-diazo-1-methyl-1,3-dihydro-indol-2-one (3265-14-3) + dibenz[b,f][1,4]oxazepine (257-07-8) → C35H25N3O3

Conditions	Yield
With p-toluenesulfonic acid monohydrate In tetrahydrofuran at 20℃; for 24h; Reagent/catalyst; diastereoselective reaction;	93%

C10H9N3O (1416060-68-8) + dibenz[b,f][1,4]oxazepine (257-07-8) → C36H27N3O3

Conditions	Yield
In tetrahydrofuran at 20℃; for 24h; diastereoselective reaction;	93%

trimethylsilyl cyanide (7677-24-9) + dibenz[b,f][1,4]oxazepine (257-07-8) → (R)-10,11-dihydrodibenzo[b,f][1,4]oxazepine-11-carbonitrile

Conditions	Yield
With 1-[3,5-bis(trifluoromethyl)phenyl]-3-{(S)[(2S,4S,5R)-5-ethyl-1-aza-bicyclo[2.2.2]oct-2-yl]-(6-methoxy-4-quinolinyl)methyl}thiourea; 2,2,2-trifluoroethanol In 1,2-dichloro-ethane at 4℃; for 30h; Catalytic behavior; Reagent/catalyst; Solvent; Temperature; enantioselective reaction;	93%

1-ethenylcyclohexene (931-49-7) + dibenz[b,f][1,4]oxazepine (257-07-8) → (R)-11-(cyclohexenylethynyl)-10,11-dihydrodibenzo[b,f][1,4]oxazepine

Conditions	Yield
With (S)-CPA; silver(I) acetate In 1,4-dioxane at 15℃; for 72h; enantioselective reaction;	92%

butanone (78-93-3) + dibenz[b,f][1,4]oxazepine (257-07-8) → (R)-1-(10,11-dihydrodibenzo[b,f][1,4]oxazepin-11-yl)butan-2-one

Conditions	Yield
With L-proline In N,N-dimethyl-formamide at 20℃; Molecular sieve; enantioselective reaction;	92%

dibenz[b,f][1,4]oxazepine (257-07-8) + 1-benzyl-3-diazo-1,3-dihydro-2H-indol-2-one (461677-71-4) → spiro[1-benzyloxindole-imidazo-bis(tetrahydro-dibenzo[1,4]oxazepine)]

Conditions	Yield
With toluene-4-sulfonic acid In tetrahydrofuran at 15 - 20℃; for 24h; diastereoselective reaction;	92%

dibenz[b,f][1,4]oxazepine (257-07-8) + 1-benzoyl-3- diazoindolin-2-one (20352-79-8) → spiro[1-benzoyloxindole-imidazo-bis(tetrahydro-dibenzo[1,4]oxazepine)]

Conditions	Yield
With toluene-4-sulfonic acid In tetrahydrofuran at 15 - 20℃; for 24h; diastereoselective reaction;	92%

dibenz[b,f][1,4]oxazepine (257-07-8) + 1-benzyl-3-diazo-1,3-dihydro-2H-indol-2-one (461677-71-4) → C41H29N3O3

Conditions	Yield
With p-toluenesulfonic acid monohydrate In diethyl ether at 20℃; for 24h; Reagent/catalyst; Solvent; diastereoselective reaction;	92%

dibenz[b,f][1,4]oxazepine (257-07-8) + 1-benzoyl-3- diazoindolin-2-one (20352-79-8) → C41H27N3O4

Conditions	Yield
In para-xylene at 20℃; for 24h; diastereoselective reaction;	92%

5-methoxylindole (1006-94-6) + dibenz[b,f][1,4]oxazepine (257-07-8) → 11-(5-methoxy-1H-indol-3-yl)-10,11-dihydrodibenzo[b,f][1,4]oxazepine

Conditions	Yield
With trifluoroacetic acid In tetrahydrofuran at 20℃; for 0.5h; Friedel-Crafts Alkylation;	91%

1-methylindole (603-76-9) + dibenz[b,f][1,4]oxazepine (257-07-8) → 11-(1-methyl-1H-indol-3-yl)-10,11-dihydrodibenzo[b,f][1,4]oxazepine

Conditions	Yield
With trifluoroacetic acid In tetrahydrofuran at 20℃; for 1.5h; Friedel-Crafts Alkylation;	91%

3-diazo-indolin-2-one (3265-29-0) + dibenz[b,f][1,4]oxazepine (257-07-8) → spiro[oxindole-imidazo-bis(tetrahydro-dibenzo[1,4]oxazepine)]

Conditions	Yield
With toluene-4-sulfonic acid In tetrahydrofuran at 15 - 20℃; for 24h; Solvent; Temperature; Reagent/catalyst; diastereoselective reaction;	91%

tert-butyl 3-diazo-2-oxoindoline-1-carboxylate (1419184-25-0) + dibenz[b,f][1,4]oxazepine (257-07-8) → spiro[tert-butyl-1-carboxylateoxindole-imidazo-bis(tetrahydro-dibenzo[1,4]oxazepine)]

Conditions	Yield
With toluene-4-sulfonic acid In tetrahydrofuran at 15 - 20℃; for 24h; diastereoselective reaction;	91%

Upstream product

• 2770-12-9 N-(2-phenoxyphenyl)formamide 
• 72084-13-0 2-phenoxybenzamide 
• 536-74-3 phenylacetylene 
• 95-55-6 2-amino-phenol 
• 100-52-7 benzaldehyde 
• 446-52-6 2-Fluorobenzaldehyde 
• 218280-60-5 C₁₃H₁₀INO 
• 36456-43-6 2-Hydroxy-N-<2-brom-benzyliden>-anilin 
• 2805-76-7 GRI 378898 
• 26260-02-6 2-iodobenzaldehyde 
• 6630-33-7 ortho-bromobenzaldehyde 
• 89-98-5 2-chloro-benzaldehyde 
• 66961-19-1 2-(2-nitrophenoxy)benzaldehyde 
• 6266-10-0 2-[(2-chlorobenzylidene)amino]phenol 

Downstream Products

• 60344-79-8 10-formyl-10H-phenoxazine 
• 835-64-3 2-(2-Hydroxyphenyl)benzoxazole 
• 3158-85-8 10H-dibenzo[b,f][1,4]oxazepin-11-one 

Relevant articles and documents

Microwave assisted synthesis of dibenzoxazepines

Dibenzo[b,f][1,4]oxazepine derivatives were synthesized in good yields and short reaction times by the reaction of 2-chlorobenzaldehydes and 2-aminophenoles in basic conditions under microwave irradiation. Copyright

Dibenz[b,e]azepines. Part 3. Acid hydrolysis

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Improved etherification procedure for the preparation of dibenz[b,f][1,4]oxazepine

(Chemical Equation Presented) The effect of temperature and catalyst on the yield and rate of the etherification reaction between 1 and 2 was investigated and alternative methods for separation of 3 and 4 from the reaction mixture have been described.

Visible-Light-Induced Cycloaddition of α-Ketoacylsilanes with Imines: Facile Access to β-Lactams

We report the synthesis of β-lactams from α-ketoacylsilanes and imines, which proceeds via a formal [2+2] photochemical cycloaddition with in situ generation of siloxyketene. This mild and operationally simple reaction proceeds in an atom-economic fashion with broad substrate scope, including aldimines, ketimines, hydrazones, and fused nitrogen heterocycles, affording a variety of important β-lactams with satisfactory diastereoselectivities in most cases. This reaction also features good functional-group tolerance, facile scalability and product diversification. Experimental and computational studies suggest that α-ketoacylsilanes can serve as photochemical precursors by engaging in a 1,3 silicon shift to the distal carbonyl group.

Annulation of Diaryl(aryl)phosphenes and Cyclic Imines to Access Benzo-δ-phospholactams

Microwave-assisted annulation of cyclic imine dibenzo[b,f][1,4]oxazepines and diaryl(aryl)phosphenes generated from diazo(aryl)methyl(diaryl)phosphine oxides through the Wolff rearrangement accesses pentacyclic benzo-δ-phospholactams, 4b,16-dihydrodibenzo

Enantioselective Copper-Catalyzed Three-Component Carboboronation of Allenes: Access to Functionalized Dibenzo [b,f][1,4]oxazepine Derivatives

A copper-catalyzed enantioselective three-component difunctionalization of allenes with seven-membered cyclic imines and bis(pinacolato)diboron (B2(Pin)2) to approach functionalized dibenzo[b,f][1,4]oxazepine derivatives is developed. The chiral products are obtained in up to 81% yield, >20:1 dr, and 98% ee when either a chiral diphosphine ligand or a chiral ferrocenyl-based P,N-ligand is used. Furthermore, the reaction exhibits reversed diastereoselectivities when the chiral diphosphine ligand and the chiral P,N-ligand are used respectively. (Figure presented.).